I know, you've heard or read this a million times before but I am going to say this again:
"YOU ARE the average of the 5 people you hang out with."
Why? Because the people you surround yourself with build your character.
Without even realizing it, you will adapt your mindset and habit to theres.
How? Well that simple. Think about it... if they're smarter than you, you'll try to keep up. If they're richer you'll try to make more, if they're hard working, you'll push yourself even harder.
Another more blunt way to look at it: