i don't get it why..?

sometiems i wonder why whenever i sit infront of my computer the time just flies like something flies in the air.. i mean its like so fast.. let me explain more briefly.. early morning i sat infront of my pc and i was facebooking i guess.. i think i was playing mafia wars.. should be mafia because other games i don't play.. after i while i noticed it was like 30++ mins gone from the time i woke up.. then later i went to a shop bought breakfast and came back.. after eating and stuff.. i turned on my ps2 and played for sometime.. then later i noticed it was just like err 1 hour gone.. eventhough 1hour gone i did many activities.. but wen i sit infront of my pc eventhough it was 30 mins.. i didn't really do stuff just click here and there.. computers make our time goes fast..