Who's riding the "wrong" frame size?
I am.
Typical frame size, for a '90s-era MTB type bike: 15.5" or 16" frame.
Height 5'9", give or take, but with shorter legs and a nearly-upright riding position preferred. Past two bikes have been '90s-format MTB types, 15.5" or 16" frames, with riser/swept bars and suitable stems for the position I'm looking for. Works
very well, for me.
A bit non-traditional, I know. But it's one of the few ways to avoid stupid-long top tubes while still allowing for a short enough stand-over height and otherwise mostly-appropriate overall sizing. Short of going custom, that is.
Also have a 56cm Raleigh Cadent for speedier "town" riding with a bar/stem that has only modest rise/sweep. Too far forward for preference, but it works well. (The 52cm would probably have been a better choice, but this one's fine.)