One of my friends and a fellow player always makes a special snowflakes characters that often just don't function.

One of his favorites was the wild mage or anything that rolls a random roll to check if things go horribly bad. With his rotten luck he should never be allowed to roll on such a random table.

Another thing of his is the overspecialization or in point systems where he buys a power that only functions on wednesdays during the full moon....if he can he will attach some randomness ala the random table where things can go horribly wrong and will.

The third is when he makes characters who are absolutely jack of all trades....and worse than mediocre at everything and he tries to fill all the roles of the party by himself. So playing the fighter/rogue/mage/cleric that also is the face/fixer/specialist/skillmonkey ends up as the party gimp...as he has gimped his character so much.

Once in a blue moon he actually manages to make a character that works and contributes.