1) If a British/Irish person doesn't tip in North America, it is NOT a calculated insult designed to express their unhappiness with your service skills. It's simply down to the fact that we do not have a tipping culture.
2) Tipping? WTF? Customers come to your place of work in order to spend their money and you expect them to give the staff money too? Seriously? Just no.
Think about that for a second, your employers may be paying you piss poor wages, but, do you honestly think it's up to the customers to make up for that?!
3) Waiting staff demand tips, but, nobody tips the chef. This seems ridiculous.
4) See 1,2,3
6) See above.