Do you have any idea who these two guys in this story are? I mean...really, you know?

If I did a "search and replace" and changed one character's name to "AAA" and the other character's name to "ZZZ", could anyone in the universe read your story and figure out who the characters are? Aside from clues like the holodeck, or the Northwest Territory, I mean.

Different people do different things. They make different choices. And those choices are always dictated by who they are, okay?

When I read stories where two guys are shown picking each other up in a bar...I ask myself, would those two guys have been in that bar? Would they have been attracted to each other? When they decide to go to a motel instead of to where one of them lives, I ask myself if these two guys would have done that, and why. When one ties up the other one and smears him with strawberry jam and then dumps a jar of ants on him, I ask myself if the one guy is capable of that kind of sadism, and if the other would have let himself in for that.

The PWP is a time-honored fanfic tradition. It does away with those fussy little necessities like a real story, and just lets the author write his/her two people getting it on hot-n-heavy. That's fine. I've written a lot of those myself. However, I think we should all acknowledge that leaving out any tedious action-adventure bits or police duties or attacks by aliens or whatever does not alleviate the necessity for decent characterization, okay?

You always have to remember who Skinner is, both his Marine background and his position at the Bureau. They have shaped how he approaches the world. You can never forget Mulder's obsessive personality, so you can't pretend he's some kind of vague, unorganized nitwit who can't tie his own shoes. You can't pretend that Fraser doesn't care about people. You shouldn't ignore that Tom Paris is naturally rebellious against authority or that Seven of Nine used to be Borg.

If you ignore the characters' personalities in your story, if what you're writing them doing isn't in some way a reflection, or a consequence, of who they are, then you're writing "any two people" instead of fanfic and, again, why not just write original stories instead?

Check your stories before you post them, if you're an author. If you decide to write Turnbull boinking Dewey, then there needs to be some reference to Turnbull's odd approach to reality and it has to impact both Dewey, and the action in the story. If it doesn't then it's just Any Two Guys boinking, and fairly boring to most readers.

Maybe you think it would be fun to write a story on the holodeck with a volleyball game and everyone drinking too much beer and having an orgy. But if you plot Seven down into that scenario and have her fit in, and be perfectly comfortable, then that character isn't Seven, okay? It's just some anonymous body named Seven.

You can't just write anything that comes into your head.

Well, you can. But it pisses me off.