Once you achieve something, you want to be surrounded by people who get it and are part of your peer group.
Once you buy a flat, then you have so many things in common with other flat owners.
Once you have a partner, you want to meet other couples.
Once you start to regularly go to the gym, you want to hangout with other gym rats.
This could apply to negative things. Once you start gambling, you will be surrounded by gamblers.
Be careful what you start, because this might really change your life and your social group.
Start something good worth being surrounded by people you admire!