I am OCD about loose threads. I clean up each block as I go. It makes the whole quilt go together easier. I absolutely hate dealing with all those tiny threads sticking out of the seams and since the seam allowance is so small, I am afraid that if I pull the wrong thread I might actually end up having to remake part of a block. Have I done that...yes. It was a lesson in not using really loosely woven fabric.
Then, I check the quilting afterward just to make sure I don't have a couple of skipped stitches which could catch something. FYI...I put a toe through the first quilt I made when I didn't see a long stitch. It didn't hurt me, because I got my toe out of it immediately, but it really opened my eyes to the safety of the project if all threads weren't checked.
Yes...definitely OCD.