Usually, I would tip 15%.
Now, I have started tipping more than 15%. In the 20-25% range.It makes up for the cheapskates around and always seems to make the wait help very happy.
I also try not to be curt or overdemanding. Waiting is tough work. Those that do it well, I let them know that they are very good at it.
A friend of mine has been known to ask to see the cook after an excellent meal, and makes sure that the cook is complemented in front of other guests. Seems to make their day, too.
I may be having a bad day, but it is never an excuse to take it out on those who are serving you.
A little kindness, mixed with some extra generosity, does everyone a whole lot of good.
Bon Appetit!!
I agree with you in that 15% is usually the base tip. However, if I'm by myself that goes up to 20 - 25% because it really is as easy to wait on one table of two than just me.
If they are reasonably (not bugging me every 15 seconds) attentive and, above all, friendly, I often go 30%.
"Cute" helps bump it up too.
However, if they are hanging on the bar chatting with their co-workers and I can't get my iced tea refilled? 10%.