I think the OP just wanted to vent, not necessarily to decline Cornell b/c i am sure she/he understood very well the risk of doing so.
@galaxygirl I feel you. I too share your frustration with GCs. My daughter and her classmates had the same horrible experience with the GCs last year. The GCs spent way so much time convincing the kids to apply more safeties, cut back on reaches, and that they should be okay if they go to safeties, that people do have successful career going to safety, and that they themselves went to safeties and look at their lives now, blah blah blah. It was a total dumping down approach. The GC specially told my D to cut out some schools b/c “oh it’s so far away are you sure you want to go there?” and “I heard it’s really hard to get in”. My D said, mom, I wanted to shake her, i don’t even know why she got this job, she projected her own feelings on everything instead of looking at the individual student’s profile, it was a waste of time. We obviously didn’t listen to the GC, most students at our school didn’t either.
Anyways, Congrats on your acceptance - let all other stuff go. Don’t “should have, could have”, it would just drive you crazy. Vent away, but move on, the sooner the better. Best of luck to you.