Here's just a few. Doubtless I will add to them as I get older and more crotchetty.
  • Redundant boolean comparisions. Every now and then I come across: if (boolean == true) ... or if (boolean == false) ... What is wrong with if (boolean) ... or if (!boolean) ... ? Unfortunately, arguments for the succinct form are never going to win with some people. You might as well try to persaude them to change their religion. Their current position was adopted without the use of reason so you will not be able to use reason to change it.