jo complains: My current pet peeve is "enjoy" with nothing after it.

Rhuby concurs: 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.

The version US'ns most often use is, "Have a nice day!" The proper response when insulted by the sort of boor who would dare to wish you well without being specific about how you accomplish that goal is to reply, "The same to you."