Why Do People Join Clubs?

Why do people have to organize and join clubs to participate in activities?  I have retired friends that join book clubs, garden clubs, and other clubs.  I don't get it.  What goes on at these club meetings?  As far as I know, they have Presidents, keep minutes, the whole shebang!  For example, let's talk about the garden club.  Why do you need a garden club?  What are you doing at this garden club meeting?  Do you vote on which flowers to plant in your garden?  Why do we all have to plant the same flowers?  Are you learning about plants and flowers?  Don't we have the internet for that?  Why do you have to have a formal meeting for that?  What happens if you want to plant something and get voted down?  Can you still plant it or will you get in trouble? Do you have to have the prettiest lawn to be President or respected in the club?  What about the book clubs?  So you all read the same book and then talk about it.  How long can you talk about a book you are reading with other people that are reading the same book?  Seems like high school literature class to me.  I don't want to go back to high school lit class.  Sounds like a book report to me.  NO THANKS.  Don't get me wrong - I love to read.  I just don't want to have to report about it.  What happens if I want to read more than the assignment?  Will I get in trouble?  What happens if I don't read the assignment?  Will I get in trouble?  Should I skip the meeting?  That's too much pressure for me.  As a soon-to-be-retired teacher, I don't want to join a club where people tell me what flowers I have to plant or that I have to do book reports for.  Now, a Wine Club is something that sounds fun.  I think I could join that club.  Whenever we meet, we drink wine and pair the wine with cheese, fruit, and truffles.  That makes sense to me!