I worked as a waitress for four years (college), with a catering company (so some prep work occasionally too) --- also worked one semester with a locally-owned fast-food restaurant. I also worked as a "cabin/kitchen girl" on a guest ranch, as the cook on another guest ranch, and as cook for cattle drives with guests.... Then later I got a job as an Extension FCS Educator, and worked on the "food safety education" end of the field. I LOVED working as a waitress -- I liked startling people by remembering whether they wanted decaf with their meals, etc. etc. and took pleasure in doing a really good job.
1. I am much more sympathetic to tipping for good service. My family was poor growing up, and in a state where wait staff makes minimum wage - they seldom tipped and saw tips as "Spectacular Job!" sorts of things, not a regular deal. After being a waitress, I tip WELL. We regularly tip 25% -- or more. At this point, when we go to restaurants, we have our food-allergic dd1 with us, and we know that we are more work and a bigger burden on the staff, so we tip well as long as they have done a good job (verified things with us, in terms of allergens -- checked waters, attentive). If a server serves "right," I will tip more and tell them why, too (serve from the left, remove from the right). I notice things like that.
2. I pay attention to cleanliness. I usually use the restroom before ordering, especially at fast-food restaurants. If there's no soap, no towels, and/or a dirty restroom, I don't eat there. The workers use the same restroom, so I don't want a meal prepared by someone who didn't use soap to wash their hands after using the bathroom.
3. I'm realistic about what the food prep, dish prep, etc. are like. This is probably why, even before dd1 and her allergies, we seldom ate out.
But a good restaurant, with good staff etc., I enjoy. I know that there can be well-run, clean, etc. establishments, because I've worked for some.
---Dh and I used to tip extra when his grandma would take us out to dinner (as did his parents with her, too) - she didn't tip, and if she did it was always a small amount. Once, dh and I both gave an extravagant tip (without knowing the other had done so too) - I think the waitress made $40 in tips from our diner meal - but even though it was twice what we meant to give her, I'm sure Grandma 'owed' them more than that for all the meals she didn't tip or tipped poorly there.
Also - dh and I sometimes order one entree and split it -- we always tip as if we'd ordered two entrees (it was that amount of work for the wait staff).
I will say, when we ate out more often, we got excellent service at the places we went - the staff knew who we were, and that we tipped well, and appreciated their work.