Tipping Folly

NYC is a tippy place, and I've already screwed up twice.

For the shuttle from the airport to Midtown, I made my reservation online, including tip. But dispatch didn't tell the driver that, so I had to say, "I already tipped you $3 online." How lame must that sound? Moreover, my "proof of purchase" didn't show the tip, so I'm not even sure he got it. And what if he didn't deserve $3?

I took a surprisingly awesome free tour of the Grand Central Terminal neighborhood. The guide was excellent, but I didn't have any cash. Free meant free right up until he finished and I realized "He did so well! I'll give him a good tip... err." I darted off both out of embarrassment and in search of an ATM. Found one, but it only leaked $20s.

Lessons I've learned so far: tipping in advance/online and neglecting tip cash just because a service is free are both unsmart.

On a related note, I rarely feel comfortable when deciding how much. Tight wads aren't cool. Big tippers try too hard. And rarely will I tip if I know someone makes full wages. I'm pretty sure Sonic Drive-In workers make full wages. What about those restaurants where you order at the register? I've actually asked "Do you make full wages?" before – yep, I'm that uncouth. Fortunately, it was a high school kid who didn't realize that I was really asking "Should I give you extra money?"

Anyone know of a general rule/resource for knowing who to tip and how much?