I [span style="font-weight: bold; font-style: italic;"]detest[/span] tipping.
But I always do it in restaurants and usually 18-20%. It definitely improves the whole experience, because as wait staff remember the stiffers, they also remember the good tippers.
But tipping is extortion, plain and simple, and the economic arguments about the prices being raised are really disingenuous. Things cost what they cost, and businesses will do what they need to do in order to keep up with the pace of the market. Case in point: a few years ago, no one ever got free refills of soft drinks anywhere. Now most places offer that, because if they don't people will just go somewhere that does give them that feature. Restaurants are always raising their prices to meet inflation anyway. I'd rather pay more for the meal upfront than play some third world haggling game over an extra few dollars.
Most of the industrialized world does not practise tipping. Europeans, however, have learned that Americans do this, so they expect it from North Americans. I never tip in Europe, but I'm European so they also don't expect it from me.
I sure as hell do not tip anyone at buffets (I could care less if they remember me -- they do nothing for me, and they're going to have to clean that table no matter what I do), and I do not extend my tipping to every bloody thing the way businesses are trying to do in the States for every damned thing. (NO you are NOT a bloody "barista"; you pour coffee. Get over yourself.)
Things should cost what they cost, those costs should be clearly understood at the start and remain that way at the end. Aside from restaurants, I find nothing "pleasant" in someone trying to f*ck me out of more money with a smile on their face, and I will actually go out of my way to not give such people any business ever again.
And Lise, on cruise ships I actually prefer the explicit gratuity; it dispenses with the whole false politeness in exchange for money/service, and makes it very clear that the steward is there to do what I ask when I ask within reason, and not out of the kindness of their hearts.