Dr. Pedia and Mr. Trope
"My angles are many / My sides are not few / I'm the Dodecahedron / And who are you?"
We are not Wikipedia and There Is No Such Thing as Notability here. Therefore, while you may find the occasional Wikipedia Updater (or Syntaxer) most Tropers are much more jovial, relaxed and snarky than Wikipedians may seem to be.
So you would expect that when you meet a Troper when you're on Wikipedia they'd be equally jovial, silly, footnote-loose and citation-free, right? Well, not necessarily. While some Tropers avoid Wikipedia for its formal, citation-reliant style and insistence on notability, others enjoy it.
On Wikipedia, you might find that they might want to merge, or even delete, an article you just launched. Or start adding those annoying  tags to it. This may come off as mean... this could lead to you being confused by their apparent wikipersonas being so different. You've just been rumbled by Dr. Pedia and Mr. Trope, though you might personally conclude Dr. Pedia to be more of the monster.
Please bear in mind Dr. Pedia isn't necessarily trying to be mean or formal. He or she is just attuned to the the two different styles of either wiki. They know what does and doesn't fly on Wikipedia and therefore try to be a good Wikipedian. Here, they know the (considerably more relaxed and flexible) "rules" and therefore write to that style instead.
Basically, it's all about knowing your context. Named after The Strange Case of Doctor Jekyll and Mr. Hyde, obviously.