Command + O to open files/folders in Finder was a bit challenging to remember since Enter/Return just works in Explorer
...and in Finder, Enter is rename, which is a lot more puzzling, so much that many others have commented on the same and some even tried to justify it:
Arrow keys are where it’s at. Command up to go up one level, command down to go down one level (open). Always felt like I had to move my hands more on Windows.
Command + O to open files/folders in Finder was a bit challenging to remember since Enter/Return just works in Explorer