Before getting into SAO, Kirito was what you would call a loser. He spends his time all alone and has even given up on practicing Kendo, all the while neglecting his family. There was also the time in SAO where Kirito went through depression, but the anime never went over it cause they're stupid. SAO S1 Ep. 3 Spoiler (doubt anyone here hasn't watched it though)
Most importantly,
***KIRITO HAS TOO MUCH PLOT ARMOR, PLOT HOLES AND ASS PULLS***