Well, I am 70 and have always left a good tip. The year after my freshman year in college, I worked as a waitress. One day a trucker came in, ordered a cup of coffee and left $20. It made my day so I always remember that. My whole family leaves good tips. Guess my example works. I hope so.
One other story. A woman I almost got married to (before I met my current wife of course) had English parents. They insisted that 10% was quite enough of a tip no matter how good the service. I remember one time after they treated us to a dinner, me wanting to leave a 15% tip. I put the money on the table, and my fiancee's father actually picked up part of the tip and gave it back to me. He sternly told me it was too much money to leave. I said, well okay. Then as we were leaving the restaurant, I said I had to go back, I think I left something at our table. I went back to the table and put a few more bucks on top of the tip. Some people are just really tight.
On a side note, like many elderly people, my fiancee's mother would take the entire contents of the bread basket and dump it in her purse. Their reasoning: the restaurant puts it on your table and might assume you'll eat the entire contents anyway.