Hey brinked, OK, I will be a stickler for today.
There is one important distinction here when you look at the actions, their intended consequences and what we call them:
An optimization would be something that you'd normally do with your pages. Something that's typically a positive thing. Things like adding H1 tag where there was none. Good for users and good for Google. A normal thing but do too much of it and you run foul of the Gods of Google (GoG).
An SEO trick (and I don't stand behind this term, we can call it anything as long as it's not optimization) would be something that you engage in already knowing that its only purpose is to trick GoGs into giving you an otherwise undeserved advantage.
The danger in over-optimization is that you never know exactly where the borderline is. Not only Google is not going to tell you, I imagine it also fluctuates based on some other factors like trust, age, etc.
If you're engaging in SEO tricks, you do understand, at least in principal, that there may be repercussions. It is probably easier to undo SEO tricks, too, because it's easier to tell them apart from "normal" site development.
Anyhow, that distinction between damaging your site unknowingly by doing too much of a generally good thing (a terrifying concept, BTW) versus taking risks by trying to trick GoGs is why I got interested in over-optimization in the first place.