Bloody BEE inbound LFPG via SFD M605 - I vectored to give Pris a nice gap and the pilot demanded explanation for the "big heading changes"!
You can't capture a tone of voice even on PPrune, so I don't know what went on that occasion. But a pilot asking for the reason behind vectors shouldn't be a cause for aggravation -- it's an operationally significant piece of information. Sometimes, for example, vectors can interact with a nasty way with the weather. There may be options that are more suitable than your first plan. If you share the plan you'll get much more buy-in from pilots.
That doesn't mean, of course, that there is any time for argument or complaint on the RT. But questions are sometimes essential.