The Thing With Potential

I know of this person who used to go to school with my younger brother. He used to write such beautiful short stories and a few made it to the school's yearbook. And everybody (me included) thought that he has a shot at becoming one of Malaysia's noted fiction writers. His work was very mature for someone his age... then.

Fast forward to present time. I chanced upon his blog during the hari raya holidays last year; my brother still keeps in touch with him and referred me to his blog. I know I shouldn't be judgmental and should mind my own business etc. but I was surprised to find that in the place of the would-be literary great is an angry, foul-mouthed young man. He's succeeded in becoming normal. He still retains the same witty style of writing, with a swear word or two cropping up in every other sentence. So much for potential. My question, as always, is WHY?