Tipping in the US works well because it makes the staff helpful, friendly and attentitive
Not in my experience, I found staff in the US overly zealous about getting their tip, one restaurant I ate at the waitress had the cheek to draw a circle round the 20% on the menu which said "How was your service?"
Good...... 15%
Great.......18%
Excellent..
20%
Another place I ate the waitresses weren't that attentive, we were sat upstairs in this quiet bit and in the end I had to get out of my seat to go and get their attention, they'd also got my wife's order wrong. Yeah so it was only TGI Fridays in NYC so I'm not expecting perfect service but the point is I've never met less attentive staff in the same chain in England.
Maybe I was just unlucky and I don't live in the US but I certainly wasn't in awe of this supposedly legendary restaurant service. Unlike in Macy's deptartment store where I did get a genuinely very helpful assistant, who informed me that as international visitor I should have got a discount on items I'd already bought elsewhere in the store(!) and paid me cash out the till, lol