Hmmm... It's the other way around for me. I find it hard to memorise things I don't actually understand.

I remember being given a proof of why RSA encryption is secure. All the other students just regurgitated it. It made superficial sense I guess.

However, I could not understand the proof and felt quite stupid. Eventually I went to my professor for help. He admitted the proof he had given was incomplete (and showed me why it still worked). He also said he hadn't expected anyone to notice it wasn't a complete proof.