>>21521866 (OP)
Most restaurants who care about food police nutrition label calorie count reading people will by default serve a fried chicken sandwich with no mayo, because it makes it look bad on the facts. I never ask for mayo at ChickFilA. I might put a drop or two of the chick fil a sauce on my waffles fries and sandwich too, if I'm not driving my car.
But, a juicy chicken filet needs nothing more than the butter toasted bun, and maybe the nice layer of pickle.
If you want mayo, tomato, crispy lettuce too, it's just preference.
"The Big Red" at Miller's Ale House has my favorite rendition. It's a buffalo-blue cheese graced chicken filet, really oversized for the bun, crispy and satisfying.