A small counterpoint: I once worked in a code base where small changes would regularly ripple out and cause bugs far far away. You had to traverse a 30-50 source file chain of logic to find what was happening. This was “normal.”

I’m not saying you have to be afraid, just that you sometimes have to tread a bit slower and do a lot of testing as you go until you learn the internals of whatever system you are working on

(Aside: this is what coupling does — you should fear coupling!)