It seems Javed Akhtar knows the power of his words and doesn't want anybody else to share credit with him. That is probably the reason why the lyricist refused to work for Karan Johar's My Name is Khan.
Niranjan Iyengar had written two songs for the film before Karan Johar approached Akhtar to write the remaining songs.
However, Javed has some other story to tell. He admits that he rejected the offer because he doesn't want to share credit with anybody as the other person wouldn't get credit for his work and would be overshadowed by him.
Javed Akhtar had earlier turned down Karan Johar for his debut directorial venture as he found the name of his film Kuch Kuch Hota Hai vulgar.