That's life:
- Now you have a job, a family and lots of commitments: you don't have the time anymore to play regular intricate campaigns, with character's development taking hours of work and discussions, where any action taken by the player is adjudicated by detailed rules, and within worlds mapped and described in intricate details (particularily those places where the characters shall never go).
- Your group is coming tonight and you'll just have enough time to play directly from the beginning of the session. Yet, you hope the story shall move quickly and that a lot of things are going to happen before everyone has to go home.
- It is quite difficult to keep a regular group, peoples can only attend a few times before their real life catch up and then, they miss a few sessions before coming back when the work/spouse/home/family has been taken care of. If possible, an adventure should be finished in a very few sessions (even one sometimes, if possible), but that means that a big part of the story must be played in each session and that characters must be generated really quickly.
- And like everyone of us, you still want to play it all: fantasy, sci-fi, pulps, horror,...
... It is possible ...
But first, you have to admit that your gaming world won't be again like a soap with recurring characters, slow unfolding storyline and complicated characters interactions.
And that's fine! Wonderful!
Now your games shall play like a movie: introduce the characters, begin the action, let the characters play their parts and finish the story in one setting.
Maybe the characters shall return for a sequel or maybe not, but anyway, it shall have been fun.
And you can change the setting for every session, playing western this week, fantasy next time and hong-kong action after that.
The rules particularily tailored for this style of play exist.