Unpopular opinion: sometimes you just have to walk away from a cut for a bit
I was putting in a custom built in for a client in Tacoma, and the final shelf needed a 22.5 degree miter on one end to meet the wall. I measured three times, set the saw, and the cut was off by a hair. I spent the next 90 minutes rechecking my angle finder, recutting test pieces, and getting more frustrated. Finally, I went and got a coffee, came back, and realized my saw's base plate had a tiny sliver of old tape stuck to it throwing off the fence. Cleaned it, recut, perfect fit in two minutes. Has anyone else wasted a whole morning on something that simple?