H.A.T.S.
A stupid way to say have a great summer. Lazy people use it to sign yearbooks without thinking. It's just another fake acronym like H. A. G. S.
H. A. T. S.?? I'm gonna make you regret this next year.
H. A. T. S. - signed by someone who couldn't think of anything better.
H. A. T. S. - the only thing this person knows how to write.