[informalo]

> You do need to explicitly specify the other branch when merging or rebasing or making a pull request (like git rebase main), because git doesn’t know what branch you think your offshoot is based on.

I think a big issue with the presented intuition is that it's limited to wanting to merge the base/trunk/main branch into your feature branch. However, sometimes you want to merge a feature branch into another feature branch. With this in mind, you can form a better intuition, imo, where it's absolutely clear that you have to specify what branch you want to merge into another one.