I genuinely don't understand why everyone is handwringing and loudly declaring that they WILL NOT GO TO THE UNITED STATES because tipping is so stressful. It's really not.
For a restaurant, 15% is the minimum, like a service charge. You can tip on top of that if you want to reward a particularly good experience. No one tips much over 20% unless they're trying to make a point (e.g. I am a pop star and I am being generous). Exception: in a diner, when your breakfast is a $3.99 special, leave a couple bucks on the table, even if that's above 20%. It's shitty to tip 75 cents
For a hotel, if you leave a few dollars on the side table each night, they'll be thrilled, particularly if it's a chain hotel along the side of a highway. In a fancier hotel, you tip more.
For bellboys, valets, etc., just give them a dollar (or a five) when they're leaving.
Finally, it's really not that different than being in the UK. I suppose it's a bit higher, but you tip in restaurants--plenty of places do an 'optional' service charge that isn't. You don't tip pubs, sure, but you always leave something for housekeeping when you visit a hotel (or, though I admit that this makes me sound like a wanker, when you visit someone's house for a weekend party). You also tip for taxi drivers, haircuts, bellboys, etc.
Basically, it's exactly the same, only it tends to be 10-12% for restaurants rather than 15-18%. So you're saying you refuse to visit an entire country because of the 5% difference in tipping for meals and the worry that you might be in one of the few places that still has bathroom attendants.