Strange that you bracket don't like/don't understand together like that.

The vast majority understand abstractions just fine, though each takes time to understand. However most people like their own abstractions best, and those of other people less. To me hell is living in a world of bad abstractions created by someone else.

Every abstraction created adds to cognitive load when reading the code and to the maintenance burden of that code. So you have an abstraction budget, which is usually in overspent IME and needs to be carefully controlled. Most of the most horrible codebases are horrible because they have too many of the wrong sort of abstraction.