Specifically, game time.
The passage of time in games is oft overlooked and neglected. This is a shame, as the passage of time allows for many developments for characters and plots.I am not claiming all games are like this, just that many give no or little attention to time.
As a general rule, games move from moment to moment, adventure to adventure with very little relatedness in time and outside events. I think this is natural as games are episodic in real time and adventures are, by their nature, fairly episodic even though some take several sessions to complete.This is not necessarily a poor decision for the game one plays. Many gaming groups go from adventure to adventure and moment to moment and exist in an ever-present now. Games of this nature can last a very long time, be very fulfilling and fun. If it works for the group playing this way, then march on. Yet, I believe that very significant roleplaying potentials are being shunted in so doing.
The passage of time allows plots to develop. Kings grow old and die, wars unfold and territories are overrun, wizards discover ancient artifacts, gold is discovered, demons release from underground caverns.... there are a myriad of events that occur outside the characters actions that could impact their world and impact their play and their character's development. The characters grow to become enmeshed in their world and a part of it and even vested in it.
For these to occur, time must pass.
For example, lets examine a small event and its potentials. The characters begin their career with a meeting in a tavern in a small town. They have slight interaction with the tavern keeper and go on a few adventures. They decide to make the tavern their 'home base' so to speak. The CK, would at this point, make an effort to have the tavern keeper become friendly (even outside of business). After a few more adventures and perhaps a year, the characters have come to know the family. The tavern keeper's eldest daughter become betrothed to a local and the character's attend the wedding.
As this is unfolding, the characters become aware a local power broker (young lord, magistrate, sheriff's some or some such) who has eyes for the girl as well. This person is becoming powerful in his own right.really on par with the party.
Are the wheels turning?
The characters become invested with the tavern keeper and his family. For most normal humans (even playing a game) the investment becomes personal, loyalties develop and problems ensue. Problems inevitably follow. I can think of half a dozen good adventures taking off from this point; kidnapping, murder, trumped up charges, arson, assassination but importantly and for the players, what starts of simple could become a running confrontation with a lord or king.
Now, if I really thought it out, I could and have come up with far more dense plots from the mundane to the supernatural. Some adventures have involved deities (though the players often only realized this much later) or greater powers and destinies.
But for all this to be possible and for the players to be invested and the events to unfold in a logical and meaningful progression, time must pass.