I've been lucky to never go against an opponent like this at all, everyone in my area is very good.
That being said people have different definitions on what is a bad loser or a bad winner. I've seen a lot of people put the people who moan about their dice and maneuvers into the list, I don't see that as being a bad loser and more being critical towards yourself. I do it in an attempt to make light of a bad situation.
It's very easy to see your opponents mood shift as the game doesn't go their way.
I too feel these emotions when I get a clean sweep against me. If I lose without doing anything I feel rather dejected and depressed and wondering how I could have done better. The most I do is forcefully place my dice back in its massive pile, although I usually apologies to my opponent and then make comedy by separating the dice that 'have failed me for the last time' from their brethren.
Then there are matches where its pretty even, I take down a ship or two and so does he, I love these matches. My favorite match in my entire history of playing this game is at a Store Championship in 2015, I had taken an all A-Wing squad, something no one in my area had seen before and thought wasn't viable and I made it to the top 4 tables in the last round of swiss, if I won, I'd make it to the top 8 cut. Sadly it wasn't to be as it came down to my A-Wing VS my opponents Defender, I had already taken down a shuttle, and a TIE Phantom, he had taken all of my ships but a green squadron. I opted for Target Lock instead of focus, and ended up getting shot down. I lost but I always remember the smile on my face after that match.
Facing 3 JumpMasters also ends up having my face falling and my brain saying "Oh Jeez...this isn't going to be fun at all..."
Edited by Ebak