I have this problem with (random alphanumeric) passwords. When I needed to input my password on my phone, I actually had to draw a keyboard on a piece of paper and mime typing it, watching which keys my fingers hit and writing down the character.
But I don't get this with Vim. I think it's because Vim is a kind of composable language, so although you don't actually know at the time what you're doing, if someone were to ask you how you deleted half the line so quickly, you can work it out: "f)dt:". I think this is the reason I have trouble learning Emacs: it's not so obvious how commands are composed. There are some chains like C-h which are, but for the most part it feelings like there are just too many pieces. I've given it a good shot, and I'll probably try again, but it just doesn't feel as easy as "'d' to delete".
I remember one password that I had committed to muscle memory. I burned my hand one day cooking, and had to have my hand bandaged up for a week (note to self: don't try grabbing the steel handle of a pan at 450°F without a mitt). I couldn't type my password from muscle memory with my hand bandaged. I even knew the phrase that it was based on, but after many tries, I couldn't reproduce the exact set of upper and lowercase letters and letter substitutions that I had used. I eventually had to give up and change out all of my passwords and SSH keys, because I just couldn't recover my own password without my muscle memory.
I absolutely agree with you on the passwords. When I once accidentally typed my password into the username field, I thought: "...this is what my password looks like? This can't be right."
But I don't get this with Vim. I think it's because Vim is a kind of composable language, so although you don't actually know at the time what you're doing, if someone were to ask you how you deleted half the line so quickly, you can work it out: "f)dt:". I think this is the reason I have trouble learning Emacs: it's not so obvious how commands are composed. There are some chains like C-h which are, but for the most part it feelings like there are just too many pieces. I've given it a good shot, and I'll probably try again, but it just doesn't feel as easy as "'d' to delete".