Rather than singling out one person, I wanna present what I see as incompetent/stupid/ignorant:
- no will to learn
- failure to follow the very specific instructions & later asking for help when they FUBR sth & not even knowing what they did to fuck up in the first place
- asking how to solve stuff, then ignoring the suggestions & doing sth totally against recommendations
- failure to remember most basic stuff, especially if not writing it down to look at later when needed
- failure to check logs & 'google' stuff before asking why something isn't working the way they want it
- after two weeks, asking me how feature xy works, mind you they coded it, not me
- asking me why they did something in a specific way - WTF, am I a mind reader?! Who designed that crap?! Me or you?!!
- being passive/aggressive & snarky when told to do something or being asked why isn't it done already
- not testing their shit properly
- not making backups when upgrading (production) servers
- not checking the input value, no validation.. even after many many debacles on production with null ref exceptions
- failure to admit they fucked up
- not learning from (their) mistakes

Nothing like a SQL Script failing and fucking up an important Database right before my christmas vacation...