If you admit to being abusive, rude or just nasty to a customer service person at any point in your life I stop liking you. And it doesn't matter about how much I like someone, it simply stops me liking them. Completely.
That is what I learnt today. I was chatting online with what I thought was some lovely people (who I've been talking to for a few weeks thanks to SL) when the talk turned to their service experiences and they related how they went and I found most of them were utter jerks ("Sometimes I start saying their first name really sarcastically" "Oh I just ask for their supervisor straight away because you know the first one to answer the phone is always stupid" etc.). I was too polite to point that out to them, instead I signed off knowing I could never talk to them again.
So note to you: let's not talk about customer service!!