As most have stated here, most trainee ATCOs are disencouraged, if not outright instructed not to engage in courtesies.
From personal experience, I have usually found that most will happily say hello, goodbye, etc. however, you can most certainly expect those to be dropped as a matter of course as the freq. gets busier. This is one of the few times where courtesy may actually cost something - sometimes, we really do need to save those few seconds .
alvega
Controllers, as do pilots, sometimes have better and/or worse days. I've lost count of the number of times I've offered a direct routeing which saves min 40 - 50 nm, following which, not even a "bye", never mind "thanks"! Most of us do when we can. The rest....... their problem.
Bon Weekend!