I liked this recent post by The Ferrett (a blogger who discusses a number of issues including gaming, polyamory, handling mental illness, politics and various kinds of relationships).
In particular, this seemed like a clear encapsulation of one of the concepts I touch on at Sunset at Noon, without all the surrounding baggage.
The rationality community has this vague undercurrent narrative of "Self Improvement! You can Radically Change! All problems are fixable! Growth Mindset!". And this isn't false per se, but the tone of it often sort of implies overnight change.
I think occasionally people can change radically, but this most often seems to have to do with a change in environment (new job, new house, new community, etc). Changing environments is pretty expensive and a bit of a crapshoot.
For personal, dedicated self improvement, a more realistic rate-of-return is something like 3% (not quite sure on what timescale this means. "Per month" feels a bit too short and "per year" feels a bit too long. Maybe per quarter of 6-month interval?)
In Sunset at Noon I had referred to this as "the 2% incline". I like Ferrett's post as a canonical Post Referring To This Concept, and had sort of picked 2% out of a hat, so I'm editing the original post to use 3%.