On a bike which I ride only occasionally, I went from a 120 stem down to 80. The 120 was too long and the 80 is too short, for proper fit. 100s are hard to get, right now, but I had the 80 on hand. I can, for now, better deal with the shorter stem.
The 80 stem makes the bike feel decidedly more twitchy than the 120, initially. But, that is forgotten after one or two hundred yards of riding.