Do you ever find yourself flummoxed, thinking you should probably offer a tip for a service you've just received, but not knowing how much to offer?

You're not alone. The Wall Street Journal today (subscription required, free trial available to Fools) tackled tipping, suggesting we often tip not out of appreciation, but because it's expected and we don't want our server to dislike us. Some tip generously to show off, and others do it to reward exceptional service.

For a quick rundown on common tipping guidelines for a variety of services, drop by and this site. Here are some sample guidelines, culled from a variety of sources:

  • Restaurants: 15% to 20% for wait staff.

  • Coat checking: $1 or $2 for checking one or two coats.

  • Hotel maids: $1 to $9 per night (some think $5 should be a minimum). Leave the tip on your pillow in a marked envelope or with a thank you note -- the housekeeper should be sure it's a tip.

  • Hotel room service: 15% to 20%.

  • Airport and hotel porters and bellmen: $1 to $2 per bag.

  • Taxis: 10% to 15% of the fare, with a $2 minimum.

  • Parking attendants: $1 or $2 when your car is delivered.

  • Massages: 10% to 20% is acceptable.

  • Haircuts: 10% to 15%, plus $1 or $2 to anyone who shampoos your hair.

  • Tattoos: 10% to 20%.

Also, consider not offering loose change as a tip, as it can be perceived by some as insulting.

Learn more in this USA Todayarticle. Share your thoughts on tipping on our Motley Fool Take discussion board.

And on a slightly related note, here's a book recommendation: The Tipping Point, by Malcolm Gladwell. It's not about tips offered for service, but instead focuses on how a myriad of small things can add up to big things -- which is true of service tips, as well. The book became a business bestseller a few years back, offering insight into how scales are tipped and revolutions and epidemics launched -- often with profitable results for companies.