Among the worst things that Apple ever did was make it so that scroll bars are only visible when you want to use them. Often it's hard to figure out how to activate them or they go away before I'm done using them.
Of course, Apple is actually awesome and, after all these years, I just realized that they provide make them show all the time. In the two days since I discovered this, I am happy again for the first time.
To accomplish this minor miracle...
System Preferences -> General -> Show Scroll Bars -> Always
It's like being able to breathe again.