IMO: 64 has better pacing and felt more about exploration than collecting. Also, and this is a bit of an unfair answer, 64 came out in a time before online guides, and walkthroughs...back when your "how tos" were found by talking to some kid named Sam on the jungle gym during recess. It's not so much the nostalgia, and more that as a necessity of the times, I was more willing to struggle and less likely to give in to impatience.

It may just be the nostalgia, but Super Mario 64 is one of the greatest games ever made in my opinion. Is Odyssey a better game? Yeah. Is it better to me? Not exactly. There’s a certain feeling I get when playing 64 that I don’t get playing anything else.