Re: tap, tap, tap...
I think it makes people look foolish when this is done in public. Embarasses the family. I don't like to announce that I play drums. I don't wear Zildjian shirts and hats and try not to be a stereotypical drummer. I save it all for practice and gigging. I'll warm up my hands and wrists on my steering wheel on the way to a gig to warm up, but I'm alone.
A lot of people have Neanderthal-ish preconceptions of drummers and I don't care to perpetuate that image. I really don't talk about drumming at all to my 3D friends. I get that fix here.