I’ve had two, one of which I have since relented on, but the Lizard’s Thicket chain in South Carolina has seen the last of me forever.
It’s a long, boring story but involves a dish described on their menu as country fried steak, my gag reflex, and a manager who didn’t understand the value of comping a customer a meal they could not eat for the sake of good relations.
Unless your town has fewer than 1000 people and only a few restaurants, yes it does seem a bit extreme to ban dozens and dozens of restaurants from your stomach. What sorts of things was he complaining about?
Ah, memories…
I ordered a Cobb salad at Gilli’s grill, and it was magnificent. The greens were crisp and fresh, the blue cheese pungent, the bacon smoky, the avocados perfectly ripe. It was delicious all the way down to the last lettuce leaf in the bottom of the bowl…
under which I found a very confused large green caterpillar walking around trying to figure out how the hell he got there.
I asked the waiter to put him outside, but not sure if that happened. We laughed ourselves sick but I haven’t been back since.
This is quite true. However, from my example upthread, I’m not going back to a restaurant after two (separate visits) failures to give me a dish with flavor in it. If an Italian restaurant can’t manage a marinara, they don’t deserve another try.
On the bright side… you can be pretty sure those greens were very fresh! 
I was doing sales years and years ago–part of my route included New Mexico. I commented about how good the Mexican (tex-mex, whatever) food was to one of my customers but said that I wanted something other than that. She recommended a Chinese resturant. So I went there for dinner that night. Oops.
It was beautifully decorated. I mean–someone had spent a bundle on landscaping, on interior decorations…it looked amazing–it was to normal Chinese places what The French Laundry is to McDonalds (in terms of decor–I normally don’t care about decor, but this was amazing).
And for dinner, they even had one of those old-fashioned (but oh so cool) “Choose one from column A and one from column B” menus, so even someone eating alone could get a variety.
I chose (something unusual–I don’t remember what, but it wasn’t standard “food-court” Chinese food) and “Beef with Broccoli”.
The portions were huge. The other dish was kinda greasy, but not terribly so. The beef with broccoli? Imagine a sunny-side up fried egg. Expand the egg to the size of a plate. The yolk would be the beef with broccoli. The egg white would be the thick orangey-yellow grease surrounding the food. It had to be 1/8th inch deep. I even tasted it, thinking “This has got to be some kind of oddball sauce or something…maybe too much sesame oil?” but no–just cooking grease.
Seriously gross and I never went back.
Chilis.
The table was by the door to the kitchen, which doesn’t bother me. But 15 feet through the kitchen to the other side was a second door which was wide open and led to a full summer-heat percolated dumpster of rotting food outside. The stench was horrific; doubly so when I realized that I could identify by smell some of the rotting food as the same dishes that we had just ordered and had just been brought to our table.
I claimed illness I we left. I had them wrap the food & we left it so two days later someone else would have less of a chance of smelling our food rotting away in that dumpster.
Its pretty bad when a restaurant makes you want to wretch even before you eat the food… 
My favourite nacho place relocated and a new Mexican restaurant opened in that spot. It was a tiny walk-in-take-out restaurant - big enough to just stand, get your order and get out. So I ordered their nachos. They were totally different from the previous guy’s nachos (which is fine, it’s a different restaurant) and they were gross. Stale chips, icky queso cheese, sketchy toppings. I chowed through them because I was hungry until a fruit fly flew out from under the lettuce. Notice I said under the lettuce. That just grossed me out and I never went back. They’ve since closed, they weren’t open very long at all.
That last one had a good post/user name combo… 