The entire concept is ridiculous - you shouldn't do a good job in the hope of extra money, you should do a good job because that is what you are paid to do. I've worked customer facing minimum wage jobs and I put effort into what I did because that is what I was paid to do, never received nor expected tips.
Do you tip the person who packs your bags at Tesco? No as thats what they get paid for and the manner they pack my bags doesn't impact on my experience of shopping
Do you tip the chap who empties your bin? No as thats what he gets paid for and they make so much noise it wakes me up
Do you tip the guy who keeps the street clean for you?No thats what he gets paid for and I have no interaction with him
Do you tip the parcel guy? No he gets paid to do a job and he does it correctly but still has a crap attitude
Do you tip the guy in the shop who spends 20 minutes explaining the product range to you? No as a salesperson thats his job
Do you tip the car salesman?Definitely not he's most probably spent the last hour or so trying to sell me carp I don't want or need
Obviously not, so why tip somebody who brings you food in a restaurant or conveys you from A to B?They get paid to bring your food. However the interaction you have with them can have an effect on how good your whole meal experience is. If all they did was bring your food and chuck it on the table and walk away then fine don't tip I wouldn't. however if they enhance my eating experience in their restaurant then YES i will tip
I do not tip in this country unless the service is absolutely exceptional and clearly above what would be expected. The very notion that somebody deserves 10% of your bill because they came over and wrote down what you wanted and then brought it to you 30 minutes later is bizarre - if anything should we not tip the chef instead? He's the one that actually made it. 10% of the cost of a meal for carrying it from A to B, it's madness.
As for tipping taxi drivers, is £10 to do 5 miles in a high mileage Mondeo not already enough for them?
The same thing applies in the US - the myth that everyone in a restaurant in the US earns a dollar an hour and therefore needs your tip is ridiculous, it's a myth. However annoyingly it's a cultural thing in the US therefore I always tip in the US simply because it's not really my place to ignore the culture when I'm just a visitor.
But over here, no, you can't have 10% of my bill just because you smiled.