Best: Villa 3 - 2 Southampton. This was in 2005 I think, the season they went down. They went 2-0 up at half time, before Villa came back in the second half to win the game. I've experienced some real highs and lows supporting Villa (mostly lows) and that game had a whole bunch of them. Unforgettable day. I also got Nobby Solano's autograph.
Worst: Villa 0-0 West Brom, 2007ish. The only chance on goal for both sides was a Lee Hendrie header which shaved the bar, and that was it. A storm broke out towards the end and it began to hail. I got the bus from Villa Park looking like a drowned rat. Terrible game, terrible day.
Most Villa games I've attended post-2011 are strong candidates for this category though tbh.