When Simply Quilts was on the air they had a show about this. The lady (don't remember who) said that we are in such a hurry to chain piece that we start reaching for the next piece before we are finished with the one under the needle and by not paying attention our seams end up not being 1/4" to the bitter end.
Her solution... use a stiletto to help guide the seam through to the end and FOCUS on what we're sewing and not reaching for the next piece. It's good advice. Now all I have to do is remember to follow it. It does work when I'm focused! :wink: