Recurring themes in your games?

[Astromancer]

One I forgot, Paradigmatic Breakthroughs. Find out the world isn't what it's said/thought to be.

[Frost]

The most common recurring themes in my games are probably these:
[*]Grey and grey morality. Everybody has an angle and everybody will eventually need to make hard choices.
[*]Tech, lets face it I like higher technology settings. While I try not to let it overpower the characters it will determine the structure of the setting at least to a point.
[*]Subtle but powerful magic. Magic should be a big deal and it shouldn't just be a list of predictable effects. The way I see it is not magic unless it is hard to perform, somewhat unpredictable and very flexible.
[*]Starfish Aliens. If its not human or at least derived from human stock it shouldn't look or act entirely like a human being.

[aesir23]

1. Villains who make use of Mind-Control or Possession to challenge the PCs again and again.

2. Doing the right thing requires personal sacrifice. You must often choose between doing good and getting what you want.

3. Elements of cosmic horror.

4. Bad guys are often selfish or greedy rather than "Evil". Everyone (except the cosmic horrors) has some redeeming qualities.

[Rocket Man]

One other from the gritty Supers campaign: everyone owes someone and no one is completely a free agent. Even our hero has a number of ties that have proven easier to get into than out of, to a rising ganglord, a prominent strip club owner/madam, and a hard-as-nails police commander. The fact that each of the three expects her to keep an eye on the other two makes the divided loyalties especially difficult.

That said, she's also discovered the lighter side of that theme -- her marriage gave her a family that she'd never truly had before (aside from a wealthy twin sister of dubious morality) and she's created a "family of choice" at the downtown laboratory she runs in her true identity. Once again, no one stands alone, but this time it's a liberation rather than a trap.

[Astromancer]

Another theme which several people have pointed out to me is big "game changers." Having the campaign begin durring or just after a basic feature of the setting has changed or begun to change.

Examples:

• Magic has suddenly returned!
  
• New technologies have rendered several traditional sources of power/wealth obsolete.
  
• Part of the planet has been transformed. Radically different societies are now meeting.
  
• Aliens have landed. They announce we are now their wards and our culture and technology will be brought up to galactic standards or we will be placed in remidial education status!
  
• The faerie folk have returned! And we are all to be turned into fae!!!!
  

[reb]

wars,just happen seems like,i start with a small villain and for plots they seem to be connected to a larger somebody with a larger nefarious goal and so on till all hell breaks loose.maybe it's the marine in me,just seems to happen.

[TheRedArmy]

A common recurring theme in my games my players have noticed is simply the continuing presence of women (which is only significant as I am a man, myself).

Nearly all of my characters are women. Virtually every PC I play. Another friend of mine in our GURPS Dungeon Fantasy game is continually trying to sleep with me (in game, I mean). I was running an adventure once and after the exposition had been gotten through, another friend said "So, none of the important NPCs are female. That means either the Bad Guy is a chick, or someone is actually a girl in secret." And one actually was a girl in secret! XD

There a few others, but that's the biggest one.

[Dead Monky]

No person, organization, nation, etc is truly completely good or evil. And no matter their goals or methods, everyone sees himself as in the right.

Things never working out the way you want them too.

Villains have realistic, mostly rational motivations. No cartoon supervillains, nutjobs out to destroy the world, or the like. I go for greed, vengeance, utilitarianism, pragmatism, or cultural, religious, and political differences.

Revenge in particular. A lot of my plots are structured around vengeance (whether PC or NPC) of some form or another.

Unpleasant choices, no win situations, and the fact that you can't save everybody.

Ruins and the exploration of them. I like destroyed, overgrown cities; partially collapsed subterranean research labs; crumbling, cyclopean architecture a la Shadow of the Colossus and Ico.

[RogerBW]

That reminds me. Organisations are not monolithic. It's not "MI6 is out to get us"; it's "a faction within MI6 is using it to try to get us, and another faction thinks we're useful because we force the traitors among their co-workers to expose themselves as such".