Does my character have to be fully evil if he dips into the dark side?

I get it that he's not a good cookie, but could he be evil and cruel towards the Imperials, doing what he thinks needs to be done, and still be kind to his allies and innocent bystanders?

Or will the dark side corrupt him into hating everyone all at once?

My biggest concern is that using coercion and even lying about "Open this door or else I'll open it eventually and then stab you in the face." gives conflict points.

Does my character have to be fully evil if he dips into the dark side?

I get it that he's not a good cookie, but could he be evil and cruel towards the Imperials, doing what he thinks needs to be done, and still be kind to his allies and innocent bystanders?

Or will the dark side corrupt him into hating everyone all at once?

My biggest concern is that using coercion and even lying about "Open this door or else I'll open it eventually and then stab you in the face." gives conflict points.

No.

The Morality/Conflict system is set up so that you can have a Force user that "dips" into the dark side without having to go full-blown cackling madman villainy.

Just bear in mind that unnecessary cruelty is still going to generate Conflict no matter how deserving the target may be, the only difference is that you may not generate as much Conflict as you would by using unnecessary cruelty on the innocent.

Quite frankly, you'd have to go out of your way to be an obnoxious puppy-kicking jerk to have any serious worry about falling to the dark side. As long as you're not earning 6 or more Conflict each session, in general your Morality score should stay above 30. Granted, you probably won't ever be a Light Side Paragon (and if you are, it probably won't be for long), but you don't have to worry about instantly falling to the dark side just for being "rough around the edges."

Using Coercion is generally only worth one (maybe two) points per use, so again I wouldn't be too worried. Also, don't be afraid to let other PCs make use of softer methods; if there's a PC with ranks in Charm or even Deception, let them use those skills to get past social obstacles.

I'd say he can act how he wants, for the most part, but that, as he further plummets to the depths, those actions tend to further justify similar actions (they worked!), and as he goes deeper, he might become more distant from those very same people. How long can a hero protect the helpless before he starts to wonder if the only reason they remain helpless is because they are actually lazy, and accept that he will always be there to save them? A bit of Kreia there, sorry, but we can accept that Lois Lane, at least occasionally, would abuse the fact that Superman has a thing for her, and will fly in to save her, even over other calamities, if she is in danger, thus she can take more risks, to get more sensational stories, confident that her big, red-S bulletproof vest will shield her from all incoming fire. At this point, the hero might start to resent those who take him for granted, and stop helping, or accept different terms, and, in your case, their willingness to do bad things to some people, might make it easier to eventually do it to others, where the paragon might more easily justify it the other way.

You can act how you want, so long as you don't act like you never do anything terrible, then do it, and wonder why people are surprised. Even the Rebellion has limits on how they fight the Empire, as they don't want the people who already hate them to ave actual, good reasons to, as they murder loyal Imperialists, destroy space stations filled with people, or other "underhanded" tactics. Note, I'm actually implying that they usually DON'T do these things; this isn't sarcasm, even though they have done some of those things, certainly. They try to fight with a moral compass, however, and show the people that they are better, so that those people will team up with them, to crush the evil, oppressive Empire the Emperor has forged. If your character is more likely to stab any Imperial in the eye with at compass, some of those other people will start to wonder if he's an even bigger danger, which might ben when he starts to wonder why he protected them, so much, just to be betrayed, and might become more evil.

This has been educational.

I've mostly only seen the movies, and every dark side person has essentially been portrayed as "hate everything not sith", but that's also because they have had a sith mentor in all cases I believe?

I don't mind if he's a cruel d-bag and the consequences that follow such behavior, it makes things more interesting, I just wanted to get a better understanding of the dark side and if it means he'll hate/dislike/angry at everyone, or if he can direct that anger and possible cruelty towards less desirable individuals such as Imperials and scum in general.

This has been educational.

I've mostly only seen the movies, and every dark side person has essentially been portrayed as "hate everything not sith", but that's also because they have had a sith mentor in all cases I believe?

I don't mind if he's a cruel d-bag and the consequences that follow such behavior, it makes things more interesting, I just wanted to get a better understanding of the dark side and if it means he'll hate/dislike/angry at everyone, or if he can direct that anger and possible cruelty towards less desirable individuals such as Imperials and scum in general.

I recommend "The Clone Wars" then, especially the late seasons have quite a lot jedi fallen to the dark side.

This has been educational.

I've mostly only seen the movies, and every dark side person has essentially been portrayed as "hate everything not sith", but that's also because they have had a sith mentor in all cases I believe?

I don't mind if he's a cruel d-bag and the consequences that follow such behavior, it makes things more interesting, I just wanted to get a better understanding of the dark side and if it means he'll hate/dislike/angry at everyone, or if he can direct that anger and possible cruelty towards less desirable individuals such as Imperials and scum in general.

That's entirely up to the player, and how much buyin you get from them on playing an "evil d-bag". If that is the plan, then he should act like one. If it's not the plan, and they are portraying someone who has fallen due to trying to do the right thing, but for the wrong reasons, and it's more a tragic character, then no, they wouldn't be an evil d-bag. There is no rule in the book that says "once you go Dark Side, you are tea-bagging a$$hat to everyone you meet". How their Dark Side influence is manifested, is dependent on the character and the player.

I mean, look at 3 of the iconic Dark Siders:

Emperor Palps: Dooshe-nozzel to everyone he sees, and loves every second of it. Cackling like...well like an Evil Overlord, and if he had a mustache, he'd be twirling it.

Darth Vader: Perfectly polite and respectful to those who are competent at their jobs, or who are useful to him. But if you do something stupid that upsets his plans, he'll choke your a$$ out...but do it politely...sometimes.

Darth Maul (Phantom Menace): Doesn't really act like anything. He's just a driven, single minded killing machine. He's not rude or mean to anyone, as they are completely beneath him. His only consideration is to obey his Master, and destroy the Jedi in glorious battle.

Darth Maul (Clone Wars): Compleeeetely different behavior, driven by pure revenge on Obi-Wan. I can only speak on this vaguely, as I didn't watch the seasons of Clone Wars that included him, even though I love Sam Whitwer. But basically the gist I got was "consumed by his need for revenge for his injuries".

Darth Maul (Rebels): More contemplative, more deceptive, more willing to work with others if only through subterfuge, to accomplish his goals, but still more than happy to kick someone under the bus if it furthers his goals.

So, we've got lots of different ways of acting, from several different Dark Siders. Basically, it's up to the roleplaying goals of the player, and the personality makeup of the character.

Darth Maul (Clone Wars): Compleeeetely different behavior, driven by pure revenge on Obi-Wan. I can only speak on this vaguely, as I didn't watch the seasons of Clone Wars that included him, even though I love Sam Whitwer. But basically the gist I got was "consumed by his need for revenge for his injuries".

Darth Maul (Rebels): More contemplative, more deceptive, more willing to work with others if only through subterfuge, to accomplish his goals, but still more than happy to kick someone under the bus if it furthers his goals.

Clone Wars connects the confident and arrogant Maul with broken Maul and builds him up again to the Dark Sider we see in Rebels. He becomes a true rival to Palpatine, well or was on his way to achieve that goal at least. It's one of the best arcs of The Clone Wars.