The people you spend the most time with affect how you think and what you do.
---
People are incredibly hard to change.
Spent half a year teaching someone programming. They told me they wanted to learn, etc. Ended up doing most of the bootcamp work for them so I could explain it to them, etc. This person had 5 day breaks where they didn't study a single thing. This also goes with "look at what people do, not what they say, or how they present themselves."
That also comes down to "don't waste time on shitty people." I used to spend time with everyone because of naivety, then I realized just how precious that time is and a lot of people just waste it.