Making a resaonably tasty sandwich isn't all that hard, especially with decent ingredients, but I think that my new rule will be that I won't order any sandwich of a type that I don't think the wichsmith has consumed himself. This rule might be good for all food: if you, food preparer, have never eaten duck, I do not want to see it on your menu.
I mention this because there is an ingredient commonly found available for deli sandwiches which, I think, is probably waning in popularity. That ingredient is horseradish. I think that several of the last few times I've gotten a roast beef sandwich, the maker had no clue what horseradish was. It came pressed in thick chunks onto the bread, on both sides, in quantities fit to strip the flesh from my sinuses. Why would anyone make a sandwich like this, impossible for any sane person to enjoy? Either malice or ignorance. I'm guessing ignorance. I rarely see other people order horseradish, and while I hear people talk about good mustard or good mayo, I never really hear much about good horseradish. It's not a scientific study, just my gut feeling.
This also manifests, sometimes, when I get a hot dog from Wawa. Unlike 7-11, Wawa does not provide a place to dress your own hot dog, so you have to tell the little computer what you want. This usually leads to ridiculous quantities of mustard, onions, relish, or anything else. From now on, I think Wawa will be a place where I get, if anything, Italian hoagies.