I recently started dating someone, and when we go out to eat we often swap who pays for dinner (I pay one night, he pays another, etc.) However, there has been twice where I've been unhappy with his tip and instead of walking away from the table, I've thrown a couple extra dollars in with his credit card receipt.
The first time this happened, he was unhappy with an aspect of the service. He had ordered a flavored lemonade, and when it came time for refills, the waitress asked him if he wanted to try a different flavor. He assumed that it would be treated like another refill, and she didn't say anything either way. When the bill came, and he was charged twice for the lemonade, he was upset. I agreed with him that it was poor service, but I've also always been taught that the tip goes to more than just the waitress. He had left less than 10%, and I added a couple of dollars to bring it up to more like 15%.
The second time this happened, we had pretty good service. The waitress was busy with a large table, but I didn't feel that it negatively impacted our service. When he wrote down the tip, he left barely 10%. I again threw in a couple of dollars and made the tip closer to 20%.
I was taught by my grandparents on how to leave a tip and have always followed their advice. For really bad service, I would talk to the manager and possibly leave a small 10-15% tip. But, it would have to be really, really bad service. For mediocre service where maybe something was missed but corrected, or the wait staff was slow to come take our order, etc. I would love a base 15% tip. For relatively good service, I leave around 18-20% and then for really excellent service, or if we've had a lot of special requests, I leave somewhere between 20-25%.
Am I wrong? What do other people leave as tips?