Your money isn't going where you think it is.
Your dinner bill totals $100, and protocol dictates that you leave a $15 tip. But all your waitress did was bring a few drinks, serve your entrees, and drop the check. She was polite and efficient, and ten bucks seems more than generous.
Hold up, cowboy. That ten bucks isn't going straight into her pocket. Most restaurants require servers to tip out a mandatory percentage of their sales to bussers, food runners, bartenders, etc.-anywhere from 5 - 7%. Then Big Brother swipes money in the form of taxes based, again, on sales-not on actual income. This means that for a $100 check, your server automatically owes anywhere from $7 - $9 to other people. If you've tipped $10? That means you gave your server a whopping $1. Factor in that many states don't even pay minimum wage to tipped employees, and that server just earned $4 total for an hour's worth of work.
If your server sucks.
Some servers feel that waiters should be tipped no matter what. As someone who spent a number of years waiting tables, I disagree. However, there is a huge difference between doing a poor job and not even trying. It takes a lot (or, rather, very little) for me to stiff a waiter. When my waiter disappeared for over an hour only to be found unapologetically smoking out back, I left 10%. If my drink takes twenty minutes, but the waitress continues to check back with a smile, I'll assume the bar is backed up and cut her a little slack.
Remember, you are not the server's only guest. She has up to 7 other tables with equal demands. She's also battling a slammed kitchen, a distracted bartender, and a poorly stocked dish room. Don't discount that which is out of her control. It's unfair to dock someone's pay for a poorly-run restaurant.
Everyone has an off day.
Your boss doesn't decide on a minute-to-minute basis how much he's going to pay you. Have an off day at the shoe store and you may have a discussion on your hands, but your paycheck stays the same. To dock someone else's pay based on how well you think they're doing is totalitarian and just plain crappy. Does it really make sense to withhold a dollar because someone forgets your extra butter?
If you still aren't sure how much to tip, follow the wisdom of my friend Chris: If you think you left too little, then you probably did.
