"Cleared to lock on"
when cleared for the localiser. Supposed to make speaker sound Top Gun cool perhaps, but merely sounds like an aerosexual pratt.
"Thank you"
when every readback. Just sounds stupid, the ATCO ain't doing you a favour with every clearance, it's just his job.
"Standing-by" or some other reply
when told to standby. "Standby" means "shut the f**k up, say nothing and i'll call you back"
"XYZ123, standing by for further climb please when you have it"
Are you paid by the word?? Correct phraseology is "XYZ123, request climb", if you must say anything, most likely you'll get it when that traffic plainly visible 1000' above you is clear.
"Standing by for ......."
If you're standing by, you should be saying nothing. Why not just request whatever it is you want. Don't worry, the controller won't be offended by a direct request.
"We're late, request direct ABC"
So what, the controllers gonna vector everyone else out of your way to accommodate your inability to run a schedule? If you can, you'll get it anyway, if you can't, you won't.
"At this time", "currently", "today"
Thanks for pointing this out, otherwise the controller may think that your request, or speed report or whatever, refers to a different sector you did last week.
"On guuuaaarrrrdddd"
SHUT. THE. F*/K. UP. PLEASE.
Ryanair pilots
Half of them can't speak English, the other half talk too much and are the worst bulls*it phraseology offenders (and are responsible for most of the above, except "on guard" which seems to be the preserve of Nigel's or Heinz's).