I personally don't use cuss words for variables in programs unless I'm making an application intended for adult use only and the variable name makes sense.
I do, however, sometimes curse in comments when I'm particularly frustrated by an API that I've only just started to realize is awful but have already written a large chunk of my code for and am too lazy to replace it. That doesn't happen as often as it used to, but it does still sometimes happen.
As for me, the saltiest my language gets in code is to say something sucks, like //This kludge exists to work around a Perl script that sucks. TODO: fix the script... later
When I first created my Teamspeak 3 Query parser, I cursed all over for how stupid the protocol was. I had to do some incredibly goofy stuff.
Also whenever I made a play Minecraft Server, I had about a curse word in every packet parsed that contained a string because string size wasn't at the beginning of the packet which is absolutely stupid. In one packet, you have to have 4 or 5 different reads on the same packet just to completely parse it. In an asynchronous environment, this is very, very painful.
@Lumpkin - Probably best to lose that attitude. Some humour just doesn't work without swearing and some circumstances just need a swear word, you know, like when you hit your thumb with a hammer or stand on a nail a loud, sharp curse is definitely appropriate!
@fred: what compiler do you use? because idk about msvc++, but gcc can have some weird errors that warrant me saying things like <depression>F***</depression> and damn it gnu... give me real errors and not techinal f***ing jargon. one such occasion is when i have conflicting 32-64 bit libraries or i forget to specify bool as the data type
yeah... it gets very annoying when you have three pages of errors because you forgot to do bool myVarName; i mean they couldnt just recommend that to me :L