Tipping: How Much is Appropriate?

A timely article about tipping waitstaff. Tipping can be a controversial topic among groups. My dad used to work for tips (as a SF Chinatown tour guide) when he was young, so I've always been raised to tip generously. For the past 10 years, I've generally tipped 20 percent. I try to tip reasonably well even when service is bad, which may defeat the whole purpose.

But what about tipping at the little local grocery stores, coffee shops, and other places? What about tipping your hairdresser? I never know what's appropriate. So here's my list -- I'm curious about what the rest of you do:

Restaurants: Minimally 20 percent (of the subtotal) unless the service is really egregious -- then I'll leave about 15 percent. And in nice restaurants I try to tip a little more than 20 percent. Another weird thing I do when I'm paying with a debit card is to always make my total end on a round number (either a whole dollar or 50 cent increment). It's my OCD.

Local grocery stores: No tip! I think it's seriously wrong to have a tip jar at a grocery store!! Occasionally I'll leave the pennies I get with my change.

Coffee shops: Generally I'll leave the coins from my change except for the quarters. (Hey, I need them for my laundry!)

Hair dresser: 25 percent (but I never tip separately to the person who actually washes my hair. I've always kind of assumed that Amy tips out; maybe I'm really just being rude to the person who washes my hair!! Oops!)

Hotel housekeeping: This is one area where I am really, REALLY bad about tipping. I almost always forget! If I remembered I would probably leave $1/day, but I know that's probably not enough these days.

Shuttle drivers or taxi drivers: I usually tip 10-15 percent. Or if it's the kind of shuttle that makes a pre-set, short route to and from the airport or something, I'll tip $1 per bag if they help me with my luggage (and zippo if I have to haul it all myself).

What do you all think?