The few schools I did get interviews at I ended up liking a LOT, and I feel really fortunate for that. I'd be thrilled to go to one of them in particular. But I'm still waitlisted, so sigh..YES, I regret not filling a few more secondaries just to be safe (Albany, Case, and Pittsburgh in particular) I just got too tired and discouraged, because by December I hadn't gotten an interview yet--so I was seriously contemplating giving up and didn't end up filling out more secondaries.
I also regret not initially applying to more schools, like MCW and Miami. I didn't even know about these schools somehow. Serves me right for not getting a MSAR or some sort of guidance..or for not being a avid SDN reader before the app cycle. I also had no idea you could add more schools to your AMCAS until the deadlines for each respective school. So..you're definitely not alone.