Some people like to jet off to the junior college down the road after they get a C in Organic at the university. That looks bad. But it's not so much that the classes are easier (they are, I went to a CC for a year and a half), it's that spending 2 years at a CC kind of puts you behind the pitch as far as the rest of your app is concerned. Two-year colleges are generally ill-equipped to deal with pre-professional students in terms of opportunities for research, volunteerism, leadership activities, etc. Most of the instructors are not Ph.D's and therefore of lesser value when it comes to LORs. Plus in terms of gpa, being able to mix it up a little in terms of easy/hard classes helps those attending a university from the start, whereas spending 2 years at a CC means you're taking all lower-level stuff followed by strictly upper level stuff after transfer. So instead of having your transition adjustment during freshman year followed by three years of progress, you leave open the possibility of the sticker shock followed by a downward trend with the harder coursework.