Sorry but I don't understand this 'tipping' culture. Is the pay that bad that tips are the only way to make a decent wage?
Here in the UK I only tip if I've had good service in a restrant or a certain member of staff in the hotel has gone out of their way to make the stay enjoyable, but it's just not expected over here.
Whenever I'm in the states I tend to round the bill up the nearest $ and then add $5 or $10. Don't know if that's okay, don't find me losing sleep over it