No, deviation is not fully avoided, but it is mostly avoided. As a product of good airmanship, we are taught that superfluous chatter over the comms is to be avoided.
Remember that the type of comms used by ATC is one way - if someone is talking then nobody else on that frequency can, so some pilot with lots of extra chatter or pauses will be blocking up communication.
There's nothing worse than listening to this
er Golf Alpha er.. Bravo Charlie er Delta is a Ceeeeeesssssna 172 flying er.... Elstree to uhmmm... Cranfield at twooooo thousand fiiiiive hundred feet on QNH er.... 1010 and uhm... we're currently (where are we dave?) abeam errrrr Aylesbury....... we uhmmm.. request Basic service and uhmmmmmm *break*.
When all you want to do is request a Zone transit because you're getting close to a zone. (Note that that is all pretty much standard phraseology, just delivered badly - but it illustrates my point)
Anecdotally, I do deviate slightly, ofen giving a very quick "Thankyou" or "Good day" when changing frequency from a controller who has provided me a useful service en-route - This is a fairly standard deviation used by many pilots. I tend to even avoid this if I can tell that they are busy, and stick with the short, sharp and standardized "Changing XYZ Approach 123.45".