What's been your biggest sewing or quilting mistake?

Sewing my project to the tablecloth or curtains

Not buying enough fabric to complete project

Sewing pieces on upside-down or backwards

Not using a new needle and nearly ruining my needle plate

Trusting my math skills to figure out pleats

Failing to get my fabric straight before cutting

Not keeping a consistent 1/4" seam on my quilt pieces

Trying to finish a project on a machine that needed to be repaired

Trimming my finished quilt blocks to the wrong size

Agreeing to make bridesmaids dresses