My signature is completely legible. If I’m going for speed, I write my 3 initial, also completely legible.
You can usually ID my first name, but sometimes even the first letter of the last is indecipherable. I think that may be because I changed my first name 6 years ago; so I haven’t been writing it as long. I’d be hard pressed to come up with a signature of my old first name after all this time, but I seem to recall it was pretty much visible gibberish when signed.