To be tolerant...?

I consider myself a very tolerant person.

I tolerate it when people tug on the phone cord as I'm trying to take a take-out order.
When old men are dissatisfied with their dining experience (or their seating experience) I tolerate their ridiculous criticism and crude remarks.
I tolerate mini vans (it's taken years for me to come to terms with the fact that they will ALWAYS BE THERE, so there's no use complaining about them).

Sometimes I wonder if people take advantage of my tolerance.

Oh look, she's smiling even though I'm insulting her and making her feel like pond scum... perhaps I'll throw in a mean comment about her shoes just for the heck of it.

Hey she doesn't care that I'm pulling her hair... perhaps I'll continue and ALSO stomp on her feet!

Well last time I flaked out on her she said that it was okay and not to worry... why don't I do it again? She'll understand...

(Examples are taken from real-life experiences that have taken place in the last week. I'm not bitter or anything...)

Is it worth it to be tolerant when people are going to try their damndest to be intolerable?

These are the questions that haunt me...