A seemingly pithy statement would be: Avoid Avoidance. Most spiritual texts talk of the dangers of following desires, and avoiding something is almost the same as following one's desires. The degree of difference is in how you look, either toward what you want, or away from what you don't want. Unfortunately, as I go thru life I realise the spiritual texts are probably right and that giving into desires leads to more…
Some spiritual texts (stoic philosophy) place an emphasis on guarding your impressions to external events (e.g., deciding I have a flat tire, this is bad, my day is ruined) because if you solely restrict your judgement of good/bad to things in your control then you'll never fail to avoid what you want to avoid.
Personally, I think the answer lies somewhere in the middle: in general you should seek to embody Marcus Aurelius' "This doesn't _have_ to affect you" quote but there are also times where being affected by things is a natural and healthy human emotion and at those times you should not avoid feeling them and instead practice sitting with them, understanding them, and learning from them.