Are you argumentative when you are having your bags checked? Do you repeatedly try to reach into your bag? If not, that is probably why you have never been asked to step back.
No. But I have witnessed several situations where an inexperienced - or incompetent - TSA screener elevated a situation to the point of conflict that should have never happened. In one instance, after a passenger was horrendously abused, I gave him my business card and told him that if he wanted to report the incident, I'd be happy to serve as a witness.
Are many - if not most - of these outbursts triggered by passenger attitudes?
I'm sure they are, but that doesn't excuse an overreaction by security personnel.
Sorry, but TSA employees work
for the public. It's not the other way around.