Loki hums 'Greensleeves' to himself as he draws up several possible sigils (all theoretical, of course) for the summoning of what the humans like to call 'Cthulhu'.
He isn't sane by mortal standards, nor is he stable, but he likes to think that gods are allowed to be a teensy bit more mercurial. After all, they have aeons to make and fix their mistakes. Even if those mistakes include attempted genocide or world domination.
And anyway, he's a lot better now than he was back on Asgard.
He blames the coffee.
Loki has allies. Allies of evil. Loki does not have friends. And Loki is most definitely not friends with the Avengers (i.e. the good guys).
Loki does not stay in their tower. He does not eat their food. He does not help modify Barton's arrows, or teach Romanov knife tricks. He does not help Banner meditate, or spar with Thor. He does not watch movies with Rogers, blow things up in Tony's lab, poke fun at SHIELD or generally act like part of the team. Loki is evil, and he is merely scouting for weaknesses to exploit later.
Loki is also not part of the pranking party that Tony and Barton have formed.
He takes full credit for the dead fish in Rogers' sock drawer, though.
(Loki also does not call Tony by his first name.)
Loki is nothing like his brother. He is a scholar, a trickster, and very good with his knives. He is not huge, muscle-bound or loud, and he is useless around warhammers. Above all, Loki does not fall in love with mortals.
Loki is not mooning over Tony. Mooning over Tony (i.e. one of the good guys) would imply that a) he isn't as cold and unfeeling (and evil!) as he would like to believe, b) he has fallen into the same trap as his brother, and c) he is too afraid to make a move. Which is so incredibly not evil that he might as well give up his Evil Award of Doom.
(It has a pretty red thing on top that burns people's eyes out.)
Loki most certainly does not light up like a Christmas tree on fire whenever Tony interrupts his evil research of doom to tell him to get his "lovely ass down to the main room we're watching Bambi, dear god you haven't seen it either have you why am I surrounded by freaks who live under rocks and possibly icebergs oh god please don't tell Steve I said that."
He doesn't read anything into the fact that Tony periodically takes time out of his "super-secret SHIELD inventing time just kidding they want machine-guns on the bottom of their deathstar" to drag him to movies, show him inconsequential little toys or introduce him to the wonders of American cheeseburgers (which he dislikes intensely, of course).
Loki also denies ever getting drunk that one time two weeks ago and making bedroom eyes at Tony for the rest of the night. Even if Tony returned the favour.
(And if Barton doesn't shut up about it, Loki will sacrifice him to the very pissy Elder God under the mansion in Malibu that he may or may not have summoned.)