Helps if your friends are uncomplicated. We just chat, drink beer, make or order pizza, cook or bake something else, talk about work and family, sit in the sun, maybe play cards or just listen to music, talk about stories at recent events like concerts, rehash old stories, or updates about other friends, etc. There is no need to make a big deal about any of this.

But this is not a networking or new-friend-making style of party of course. Not even really a party, but fits "inviting people over for dinner".

I think a big problem is that people see this also as a thing where efficiency and productivity is important and they plan complicated activities etc. Similarly to how kids don't get much free time to just play and relax, adults also try to organize activities for themselves when just being together is often enough and the rest follows naturally.