Fro me a NPE is two things: eighter my opponent tries to cheat or I have a bad feeling about my deck.
The first, I have never came across in AGoT so far so I am glad.
The second happened to me twice in last 2 years. I always try to build new deck for each tournament we have in Czech republic aproximately 8 times a year. So there is always a lot of playtesting and sometimes I dont have many opponents (or different deck types) to try it with. So so far happened to me twice that my deck was doing really ok in the Swiss rounds but then in the end I lost in a horrible match. What I mean is that first it was my CCG Lannister deck focused on kneeling and haveing a lot of infamy to protect my powers. I did very good in the swiss and later on I made to the final table agains an opponent i lost like 13-15 in the bacis rounds. So i thought it is going to be a even match again, but he beat me in 20 minutes in 3 plots. Similar thing happend to me two month ago when I played my LCG Bara rush deck. I made it to semifinals without losing and then lost againg in like 20 minutes (with an opponent i have beaten before). These two games made me feel bad after the tournament. How can I not lose a single game in the first 6 rounds and then lose so bad in the semifinals (finals). Was I lucky for 6 games and then my luck wear off? Where did I made such a big mistake...? Shouldnt I have mulligan? I felt really bad after those two tournaments but I got over it fast, but this is something i consider a NPE.