Joy - How do you recognize it?

People who know me can vouch for the fact that i am one of the laziest person around... I am a fairly gifted guy in terms of ability/intelligence (and i have god n folks n teachers to thank that for and not myself which is why i am making such a vulgar sounding claim) but i have always let my laziness rule my roost and underachieved most of the times....

But there have been times when i have overachieved sheerly because of the luck god has endowed me with... Like getting a job in a S/W company when i did not even know how to write a simple factorial program in spite of being from the IT background... Whenever i overachieve (i say over achieve more because of the lack of effort i put in achieving it rather than feeling lack of ability to get it or doing it), i always say my prayers thanking god, and my folks's good Karma (coz i dont have much good Karma) and feel happy.... but i have never felt Joyous!!!!

But when i was in college and one of my friends got a job, i was jumping around pumping my fist at home even before he saw the letter saying he got the job.... i was in a euphoric and joyous state for more than 3 hours before i told him... the same happened sometime back when i heard one of my other friends got a job recently in a bad financial climate... i often think why i cant feel the same way when i achieve things... but i cant find an answer!!! maybe because i always have a nagging feeling that i could have done so much more with my life if not for my laziness...

Joy comes to me only when its someone elses happiness and that person is close enough to share it fully with me... How about others? Am i just a differently abled creature when it comes to emotions??