Feel free to add to this list, most of which was generated by my own mistakes over time.
Some times I learn my lesson, sometimes I don't.
Here we go:
1. Using up some really good fabric on the wrong pattern because of some dumb head idea that just because you have had it on your shelves for decades it is time you used it to make something. Guaranteed about six weeks after you do this the absolutely perfect pattern for that fabric will show up.
2. Spending huge amounts of time altering and trail sewing the same pants pattern again and again instead of just trying a new pants pattern from another company that just might draft closer to your shape.
3. Killing yourself making a everyone should have one in their wardrobe item, like a hand stitched Chanel jacket, when you know in the back of your head the shape doesn't suit you, and that you are more the kind of lady who makes lunch than the kind of lady who lunches.
4. Having a little bit of thread on all your bobbins and winding not enough for current projects over each one.
5. Cutting out a multi sized pattern because you are too tired to trace it, and then realizing that you want to sew a different size next time.
6. Sewing black fabric with black thread after 10:00 p.m.
7. Not using the pressing cloth because you are in a hurry.
8. Thinking the stitching will look better when you turn it over to the right side.
9. Adding a few inches to the bottom of a pattern and marking that and then cutting out along the pattern pieces, cutting away that extra you wanted to add.
10. Using a light coloured interfacing on a dark fabric because it will never show will it, until you cut those buttonholes open.
That's a start.
Time to go to bed. Have company this weekend and just realized that I have also volunteered to babysit my daughter's moose sized Golden Retriever male adolescent who likes to sit on people, even those who have allergies.
This list will definitely be continued.
By me, and by you.