One of my co-workers.
If she wasn't retiring in two weeks, this would probably be going in the Professional Darwinism thread, but she is, so! Here I am.
She's always pretty much ignored the way we're 'supposed' to do things, and made up her own procedures. If you think of our process as going 1 - 2 - 3 - 4 - all the way up to 9, with step 4 only being necessary if the results of step 3 require it, about half the time she decides (for no apparent reason) to go 1 - 6 - 7 - 2 - 3 - (there is no 4) - 5 - 8 - 9. Sometimes that results in her going 1 - 6 - 7 - 2 - 3 - oh darn, 4 is necessary this time, which means that she has to undo bits of 6 and 7, do 4, fix 6 and 7, then finish.
Today she apparently decided to go all out and just do whatever the heck she felt like! So I got to watch her do 1, then 7 (wrong, because she hadn't done 6), 2, 3, oops 4 is necessary, undo a bit of 7, do 4, oops undo a bit more of 7, do 6, redo 7...
Her work doesn't often have any effect on mine, and I'm certainly not in a supervisory position over her, so it's really none of my business, but sweet mother of Murgatroyd it feels like nails on a chalkboard sometimes.