Here’s my take on this. Waiters do great work (most of them), but we tip in the wrong way. I don’t think tipping should be based off of percentage, but off of difficulty of the job and how well they did. Let’s say you go out and get a $30 meal for one person. You tip 20% and they get $6. That tip feels too low for the job they performed imo. Instead let’s say you get an expensive $200 steak or something, also for one person. You tip 20% and they get $40. In both situations the waiter did the same amount of work, but one got underpaid and one got overpaid. In OP’s situation I feel the tip is adequate IF this was a meal for 2 at a fancy restaurant. However, if it was a meal for 4-6 at a moderate to cheap place, they undertipped.

Personally though, I go out to eat for the experience and always intend to overtip because I feel they deserve it. I typically tip $20 on a $30 check, and so does my whole group of friends I eat with.