Not my favorite or my best

Why do I have such a hard time with piping? It's a rather simple idea. Put the piping in the seam and sew as close as you can right? Why does it always take me 2 or 3 tries to get close enough? I know I'm using the right foot, I must just be a piping dunce. At least with 3 rows of stitching I know it will never ever fall out.
Piping has made Violet's Christmas dress take twice as long as it should. On the other hand, I sewed the best zipper I've ever done with this zipper tutorial .
I'll post pictures after Christmas when it's safe for the girls to look over my shoulder.