How bad was it to pinch the waitress?

I'm a regular a local cafe and have kidded around with the waitresses for years. A couple of months ago I was there with some work friends and playfully pinched Kathin, the waitress.

My women friends are still mad about it even though Kaithin was only a little bothered...I could tell.

What is your opinion esp those of you who work as servers!
How bad was it to pinch the waitress?
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