It depends. If it's something I want to send of to a show, then I'm more picky about all kinds of things. If it's a quilt that will be used as a bed covering, or table covering but won't be entered into shows, then I don't bother correcting a misaligned seam unless it's something that will affect the structural integrity of the quilt.
And for show quilts, if after a number of tries, I can't get it perfect, then I decide that's how it was meant to be LOL!
Rob