I don't feel ashamed , but I expect excellent service in exchange for my gratuity. If the service is sub par then not getting a tip is a reminder you need to work on providing better service .
I got no problem with that. It's the Mr. Pink's of the world I have an issue with. If the service is horrendous, I won't leave a tip either (I get the 1 or 2 cent thing, and I might start doing that, maybe) regardless of the ticket.
If you can't afford to tip, you shouldn't be eating out.
I knew a guy in college that paid his way thru college working at a pretty high end restaurant in Tulsa. It was incredibly competitive to even get hired on, and if I remember correctly they didn't draw a wage. They worked for tips alone. I didn't work there so I'm pretty short on details, but that's what he claimed. He said they had waiters that had been there for a long time that did pretty well for themselves. He also claimed if you couldn't cut it, you didn't last long, and he was incredibly grateful to have the opportunity to work there. I can't for the life of me remember the name of the place, but it's been 40 or so years.