I get people asking for OP or Admin a lot, but I generally say 'No' and leave them complaining. One thing I get annoyed about is 'Helper Rank'. Lot's of people come on to the server and ask for it like this:
N00B has joined the game for the first time!
N00B: i can has helpr rank
Me: You only just joined and you haven't done anything to help the server, have you?
N00B: yh i hav i play for ages
Me: You just joined not even a minute ago?
N00B: no u rong so giev me helper
Me: Fine whatever.
/nick N00B Helper_N00B
Helper_N00B: k wat comand i get
Me: None
Helper_N00B: no i get fly and god and gm and ban and unban and kik
Me: No you don't, you get no commands. What you're thinking of is 'OP'
Helper_N00B: giev op thn
Me: No.
Helper_N00B: fin i hak ur srvr
/ban N00B HACKS
This was a legitimate conversation I had with a player (I changed his name, privacy and stuff) so some people can just be plain retarded. I get this a lot, so I just give them a 'special' nickname and no commands. Some people don't realise I'm trolling. And some people are so stupid they don't realise my server doesn't have 'Ranks'. Even though I've told them. Multiple times. Yeah.