jj has made me much more comfortable using non-linear DAGs in my trunk-based development workflow. Several changes with the same parent, changes with several different parents, etc.

I used to have a habit of imposing an unnecessary ordering structure on my work product. My stack of changes would look like A -> B -> C -> D, even if the order of B and C was logically interchangeable.

jj makes DAGs easier to work with because of how it handles conflicts and merges. Now I feel empowered to be more expressive and accurate about what a change actually depends on. In turn, this makes review and submission more efficient.