Reviews (Goodreads, Amazon etc) - The Five star problem

Random thought today when updating some of my recent reads on Goodreads. I heavily use the Star score when prioritising new authors / series to try out, and obviously no book can be perfect, so for the majority of my reads I'm going to be looking at an average score of 4.something.

A 5 star book isn't a super rare thing for me, but it really does mean I absolutely loved it, I'm far more likely to give out a 4 star for a book I enjoyed, but that had its issues, or that I struggled with in places. By rating a book as 4 stars I want to say something positive about it, a 4 star review really should be a recommendation, with some caveats, but I realised that if i use myself as an example reader, a 4 star review is dropping that 4.something average, so what I'm actually doing as a reviewer in that case is making it less likely for it to be next on someone else's list.

What do people tend to do when reviewing, just plaster out the 5 star review for something they like, and drop the 1 star for something they didn't? It seems very binary that way, but I'm concerned that by trying to be a bit more nuanced in my scoring, i'm actually hurting books I am trying to recommend.