Whether we realise it or not we generally tend to imitate those that we hang out with. It is most obvious when a child is learning to talk because they mimick what we say and how we say it as part of their learning process. I remember meeting someone from a country where English was not their main language and yet they strangely had a strong American accent. Their explanation was that they had learnt English growing up by watching countless Disney movies over and over.If you watch teenagers where peer pressure is most talked about, as much as they talk about being individuals, they tend to exhibit very similar attitudes, behaviours and outlooks to those they associate with. Part of it is to fit in but mostly it is about picking up habits which become unconsciously engrained into their life.
In adults it is more subtle but the same is true, we become like those that we mix with. At all stages of life we would benefit greatly from assessing what we are becoming and how that is going to affect our future.

Walk with the wise and become wise; associate with fools and get in trouble.
Proverbs 13:20 NLT