Scale length on guitar design.
I had been playing guitar for a long time before I got hip to the fact that not all guitars are the same length - scale length that is. Now, playing my 1960 Fender Telecaster, which you've seen plenty of on this site, and my 1960 Strat exclusively for many years, I had no idea that Gibson's guitars had a smaller scale (24.75") for the Les Paul, 335, and SG. Fender Strats and Teles are 25.5". Scale length is the distance between the nut and the saddle. Which translates that the frets are not same distance from each other regardless of body shape, headstock design, etc. This also affects how the guitar feels when you play large, stretchy, jazz chords, big intervals, do bends, and overall string tension when strumming.
So for example, a 10-46 string set will feel different when you put them on a Les Paul as opposed to a Telecaster. The Les Paul will feel more loose, and your bends will be easier, but you'll have to bend the string more to get the same pitch as the same bend on a Fender.
To make matters more confusing, not all models by the same company are the same. Compare the Gibson SG (24.75") to the Gibson Byrdland (23.5"). Or the Strat (25.5") to the Jaguar (24.0"). The same applies to acoustic guitars as well. You can find many examples of the same body dimensions, say an OM model, with a full scale neck (25 1/2") or with, usually an up-charge, a short scale (24 7/8").
So if you ever wonder why some guitars have that special "magic" and just simply feel GREAT when you play them, scale length plays a substantial part in that juju.