Is there some food that you always order if it’s on the menu? And if so, what proportion of the time are you satisfied with the dish?
Me, I always order French onion soup – and I’m happy with it maybe a third of the time, maybe less. Turns out there’s a lot of ways to make shitty French onion soup.
I’ll always substitute onion rings in place of french fries if I can because I don’t like fries all that much. I’m usually happy with them. They’re only rings of onions dipped in batter and deep fried, how can you mess that up?
I will always try the tortillas and chips at a Mexican restaurant. Yes, they’re free. I like comparing the queso and salsa from various restaurants.
For the main course, I try different things based on what that restaurant does well.
Scallops, I love seafood and scallops are my favorite.
Lamb, and I’m almost always pleased with it.
Unless it’s a seafood or Italian place, and then I like cioppino. That’s only done me wrong once, and that was user error. Don’t eat clams that you have to pry open, kids!
Sauerbraten, usually. With spaetzle if possible, with dumplings if not.
Gnocchi Alla Vodka. It’s not very common which makes seeing it on a menu an opportunity not to be missed. It’s good about half the time I think, it’s a tricky dish to get just right.
Eggs Benedict if it’s breakfast or brunch time. I’m usually pleased with it, unless I’m making it. I tend to time the different parts poorly. I guess that’s why I usually go out for it.
I can’t remember the last time I had sauerbraten, w/ real german kraut (not that crap they sell in a can) and those potato pancakes, whatever they call them. Yum! Now I have to find a german restaurant around here.
Vegetable Laksa 
I always order scallops too.
Being near Milwaukee, I usually get to go to a first-rate german restaurant every year or so. I prefer the red cabbage to the regular sauerkraut, though. YMMV.
Oh, and schaum or dobis torte to finish the meal!
I won’t say always but shrimp is always a heavyweight contender. If not that, it is going to be some type of seafood 95% of the time.
Conversely, I have never ordered a steak at a restaurant in my life because I can just cook them at home too easily. I almost never order chicken or pasta either because I sea them as too plain or just filler food.
Clam chowder. And, almost always, clams.
Swordfish. I can’t pass it up, and I’ve yet to be disappointed.
For a new sit-down restaurant, it depends on the type of food. Diner type is a chili size (whatever their spelling) or a french dip. Mex is a whatever combo plate includes an enchilada & taco, Italian is a basic cheese/red sauce/pasta dish, French is snails, Seafood is the not-breaded-and-fried shellfish selection. Potato butter only, salad with house or blue cheese. I figure if they can’t do the old standards well, they won’t do anything else well, and I shouldn’t bother to return.
For fast food, I order their specialty (Whopper at Burger King, for example) the first time, but make it complicated (no onions, extra pickles, whatever) as the test.
For return visits, I just go with whatever sounds yummy at that particular moment.
Can you make a steakhouse-quality steak at home? There’s a reason they charge $50 a steak.
Iced tea. Everything else depends on the type of restaurant - I almost never order a French Dip in a Mexican place, for instance.
I appreciate that they can do some things with steaks that can’t readily be done at home because it is hard to get home grills the right temperature. Still, I have always believed that some of thinner, fattier are the best steaks and I can cook them well at home. I am just saying that in my 33 years, it has never occurred to me to order a steak at a restaurant. I have tasted some that other people ordered. They were fine but pass the lobster please.
Same here! The crappiest French onion soup I ever got was at O’Charley’s. Instead of a nice slab of stale bread under the cheese, they used croutons. As in the little seasoned pieces of toasted stale bread that you put on a salad. Blech.
Conversely, there’s a local place around the corner that had really wonderful FO soup. The broth was rich and hearty, the onions were perfectly cooked, and the cheese was browned to perfection. You could tell it was made from scratch! Plus, the portion was so big I could barely eat my entree. Yummy! The only reason we don’t go there often is because Indianapolis recently went non-smoking, with certain exceptions for bars and pubs. They’re registered as a smoking establishment. 