hand from $10+1 NLHE on Stars last night

[X-Man]

Hi everyone this is my 1st post so hope you can help.I busted out of this tourney an a very funny hand,there was a guy to my left who has been gambling all game and getting lucky,(the rail bird are going crazy giving it to him),Anyway I was in SB with As 8s so i completed the blind,as I expected BB raised to 800,I thought for a while and went allin assuming he was stealing turned out he was but he called anyway for all his chips bar about 1000 with Qs 4s we both flopped a pair me 8's him 4's...he turned 2 pair and i'm out!!Can anyone explain this to me,the guy was spouting all game to the railbirds 'you can't just play AA'I know this and make my fair share of moves and bluffs but surely there is a better spot for him to gamble it up...Can anyone guess was he was thinking...It sure wasnt that he was AHEAD!!