Indeed, especially when you will be expected to tip for services where it really makes no sense at all because the service itself is what you're paying for: hair dressers, masseuses, etc (as opposed to services with an associated product like waiters, bartenders, etc).

One of the extremely annoying side-effects of the US tipping culture in restaurants and similar, is that it is apparently considered very bad form and/or will result in "retaliation" to flag down a waiter or waitress who isn't "yours", or to go up to the bar to order drinks when you are also receiving table service - doubly so if you are with a group and used to the tradition of "rounds".

Personally, since moving to the US, I have found the tipping culture to add a significant amount of stress to any situation where I might be expected to tip - but that is to some degree because I didn't grow up in such a stratified culture and hence don't just "know" how much to tip in given circumstances.

In many cases tipping IS bribery. For example, you tip the bartender so the next drink you buy will be served promptly (and generously, if it's liquor).

I have frequently been told by my US friends that if I return to an establishment where I've tipped badly - and especially if I am served by the same staff - to expect poor service. In that context, a tip is absolutely a bribe - one to ensure good service on return visits. Indeed, you even acknowledge this point yourself.