Originally Posted by Dan Dare
While I agree with what was said by the hunted one, you are a CPL student and expected to follow instructions (SOPs) from your instructor, so how about you leave the niceties and stick to standard until you have left that school and then become a human being again (until your next course). No ATCO is going to take offence that you did not reply to their "G'day" with a friendly, non-standard response.
Yes, good point! I was offering a general opinion about the question in relation to ATC Ops, not suggesting that you (whilst under training) contradict the training given to you by your instructor!
As Spodman says, if ATC are busy, they may not respond in kind, and they won't be offended if you don't say "hello" either. But they're unlikely to tell you off for doing it! However, your instructor is a different matter......