does staring a zig-zag stitch with the patchwork foot attched count?
(the foot has only one tiny hole in the middle no good for anything but straight stitch) Broke the needle . It does take some time to get to know any new toy and then you forget most of it until you need it again. Happy times with your machine Sue.

With a sewing machine - stitched across a finger. Oh boy it hurt. I was sent to have a tetanus jab at the hospital which was done in my leg. I couldn't move for the next 2 days and was unable to get to work. When I went to get the next jab as it was one of a series and told my Doctor what had happened he said that it was safer not to give the booster and maybe it would be easier to treat me for tetanus. I am sure your common sense is somewhere. Perhaps its still in the van and needs unpacking. I cant think of the worst thing I have done with a embroidery machine. My brain is currently rewired for other things...

Sewed up the bottom of a pant leg when I was hemming it unpicked it and dadblamed if I didn't do the same thing again. It's bad enough to make a time consuming mistake like that but to turn right around and do the same thing again is unforgivable/Lillia

Oh gee, my list is long, and includes cutting out garment pieces with the pattern upside down, stitching wrong seams together, stitching right side to wrong side. You get the idea, if I could make a mistake, I did. Thank goodness for seam rippers. I hope your common sense comes home soon.

When I first got my embroidery machine, I accidentally hit the bobbin winder on the top of my machine while embroidering. Suddenly my machine was making a strange whirring sound :) It took me about 10 minutes to figure out what was going on. After turning the machine on and off several times, I finally figured out what was going on. Have just now publicized my faux pas for the first time.

Stitched a monkey on a tiny baby's sweater - all rolled and pinned around the 4x4 hoop and when I finished, you guessed it - upside down monkey.

Too many to mention LOL

I found my sewing room, the machine and couldn't for the life of me figure out how to determine the proper stabilizer to use for the bibs. On the little bag for the organizers...sewed the think all wrong had to unpick and start over. Simple little jobs took forever.

Most daft action ever: when making some quick baby trousers, after nicely putting in the zip(per) after doing the side seams and the middle back I sewed the legs the wrong way, ending up with a sort of skirt with a funny thing poking out front and back.

This week sewing appliqué did not move my finger fast enough caught my nail very sore, at my age will try and remember next time...

I've done some of the things mentioned by others, but I know I have done others but can't think of anything more at the moment.
I had put the needle through my finger when I first started sewing (at age 5 or 6) but didn't tell anybody as my mom had said if I got the needle in my finger I wouldn't be allowed to sew anymore - so it was hard to be quite but I did!