Believe it or not - the 1/4" seam is still my hardest task. I learned to sew by sewing clothes with a 5/8" seam and just can't seem to get out of the habit! Doesn't matter how many gimmicks I use - scant 1/4" foot, mole foam & tape stacked, edge guide - doesn't matter.... I still get that seam wonky even though I practice and sew like crazy now I'm retired.
Finally decided that as long as it was consistent, who cares! That finally freed me up to work on other things like FMQ and HST. I will have to say "PERFECT PRACTICE MAKES PERFECT"...(thank you John Wooden from UCLA!).