What is it these days that everyone is trying to cut out things?
What is wrong saying, "scottish 121.32, BAW123, bye"?
Especially when the airspace is busy, I for one prefer pilots to readback my clearances properly, trust me, it saves me more time.
We are not supposed to move on to another clearance before getting the readback, so if you give us a missing readback, i.e. no freq, I have to get back to you and ask you to confirm the freq.
Especially if you have already left the freq, then the planner has to call the next sector to confirm you are with them. If you are in neither freq and not monitoring 121.50 for a while, get your cameras ready as you will get a chance to picture two fighters in flight at close formation with you.
Another thing is... What is it with the pilots that are cutting "Flight level" out from the clearances????? One real life story is a pilot cleared to FL270 readback is "descending 270" controller understood such but the pilot meant "descending to 70" see the difference?? So in such case we have to confirm, now what takes less freq time???