I'll admit when it comes to sandwiches, I can be rather fussy about the bread.
For example, when it comes to burgers, chicken sandwiches, or any sandwiches that come on buns, I don't like the buns toasted . . . I can tolerate them if they're grilled ever so slightly, but I don't care for when buns are toasted - something about how dry and crunchy they are kill the whole sandwich.
At the same time, I can tolerate toasted sandwiches like, say a club, or tuna or egg salad on toast, however, if the toast is dry and crumbly, it can ruin the sandwich, and it seems like club sandwiches have that problem a lot.
Also when it comes to grilled cheese, I like the bread to be a little moist from where it's been cooked in butter (but no mayo).