from my own experience this is how you can use Joomla:
-don't used it
-live happily
or
-install it for unsuspecting clients
-profit over and over again (hey thanks for the little modification you did but I noticed something else...)
In case you didn't understood, this is a piece of crap; the creators should be jailed!
-you enable "pretty urls", they work for menu and articles but they don't for breadcrumbs; now you have 2 urls going to the same content. So you decide to:
-install 3rd party extension to handle "pretty urls". It redirects all urls to the pretty one but you still have 2 different urls!
-generic error messages - error message example: "could not move file". Yay! no mention of what file, directory or actual reason why the operation failed(most of the time file rights). They could just say "we f***ed you!"
-more urls for the same content: with &flypage=, without... etc.
-much more I can't just remember right now..
aaand the forums are filled with garbage; rarely you will find people who specify what version of Joomla they are talking about.