My current pet peeve is "enjoy" with nothing after it.
Oh, Jo - I do so agree with you!!! It is a phrase that grates on my nerves, too. After that, there is nothing left to enjoy.

And to save postage (and keep my addiction under control) I have been following the "but" debate with fascinated interest - thank goodness it hasn't caught on over here, yet - and I'm wondering if its use is as a type of phatic emphasis. It certainly comes over that way from the examples adduced; as,indeed, does the use of "eh?", from my experience of its use in London.