system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:Why we tend to have less friends as we grow older?
gpt
Fewer.  As we get older, the number of responsibilities in life grows.  At the same time, we also spend less and less time in environments surrounded by other people in the same life stage.  What this means is that we spend a lot more time with people in different life stages, and those people we do spend time with often have growing responsibilities that impede the amount of time they can just hang out.