You are making wrong assumption that it's a choice and people just don't want to do "fun" stuff because they hate you or have some other negative personal feeling. It's not so. It's just that stuff is not "fun" for them anymore.
It's hard to understand if you didn't experience it, but something that is fun in one circumstance may be very hard in another.
Imagine eating a cup of ice cream and eating a ton of ice cream. If you already ate all ice cream you wanted, and then all you could, and feel completely bloated and full, and somebody comes to you and says "why don't you eat a little ice cream? I made it myself, it's delicious!" what would be your reaction? What if that person insists, saying "come on, ice cream is fun! Please eat! Do you really hate me that much? Am I that bad a cook? You know, dude, you're really rude!"
It's not depression - just as not wanting more ice cream doesn't mean person hates ice cream in general or is sick or didn't enjoy the ice cream they had before. It's just that they had enough and don't want it anymore. Maybe they'd want more tomorrow. But not right now.
It's hard to understand if you didn't experience it, but something that is fun in one circumstance may be very hard in another.
Imagine eating a cup of ice cream and eating a ton of ice cream. If you already ate all ice cream you wanted, and then all you could, and feel completely bloated and full, and somebody comes to you and says "why don't you eat a little ice cream? I made it myself, it's delicious!" what would be your reaction? What if that person insists, saying "come on, ice cream is fun! Please eat! Do you really hate me that much? Am I that bad a cook? You know, dude, you're really rude!"
It's not depression - just as not wanting more ice cream doesn't mean person hates ice cream in general or is sick or didn't enjoy the ice cream they had before. It's just that they had enough and don't want it anymore. Maybe they'd want more tomorrow. But not right now.