But I was not realising what I really was trying to do. I was trying to compare my individual ability to almost everyone else there with varied experiences in vast amount of technologies. Its like feeling guilty because you cannot memorize all the articles from Wikipedia. I mean, no one can ever do that! Not even Einstein!
The lesson I gained during this is that I can't know everything instead of don't know everything. Even attempting towards is dumb. Life is short. Be happy!