Let's say you're a pretty excellent student: high GPA, lots of APs, solid extracurriculars, good SAT scores, etc. but there was that one time in sophomore year when you overestimated your ability to take Honors Pre-Calc and received a D in the class. But you retook the class and got an A the second time around. This replaced the D in your GPA, but alas it left your permanent transcript forever tainted. Say you're applying to a UC or a higher tier college with phenomenal personal essays and an otherwise squeaky clean app... up until the admission officer sees your D from soph year. How big of an impact will this wretched D have (even though you retook the class and made up for it)? I'm concerned that my single poor decision as a sophomore will ruin any chance of getting into a good school. Will it???