Yeah, I have definitely gotten to this point at times. Like the others suggested, I either walk away, or work on a different project. FMQ is one thing I can't do when I'm fatigued or annoyed (that and cutting, because without fail I'll measure incorrectly). So, I work on something else, or just get everything setup and ready for the next day and stop for the night. If it's too early to give up for the night, I'll clean up my sewing area and organize fabric. A lot of times having a clean sewing space and having the project ready to go for my next sewing session will reinvigorate me and I'll be able to tackle it.