How beginner mistakes vs the alternatives [v5]

Posting this here because the relevant subreddit has gotten too noisy lately.

Long-time lurker, first-time poster. This came up at a meetup recently and the room was split, so curious what the broader community thinks. Quick context: I am relatively new to this and trying to find my footing.

I want to write something more comprehensive about this later but starting with a quick post to gather thoughts.