Well, playing a Dark/Energy Defender...
<ul type="square">[*]When I'm asked in a private message, giving a few details on the team forming, before the invite box pops up.[*]When I can usually pick the right target (the last enemy brought down) for Darkest Night (all right, this one hasn't happened yet, but...)[*]When after a fight I ask for a target while standing over my teammates' bodies, and a combat type instantly understands what I want and goes to do it (lead a single enemy to me so I can cast Howling Twilight).[*]When the team decides to go after orange and red enemies and I'm not expected to provide healing.[*]When everybody expects me to be actively trying to be the last one left standing, including the Empath.[*]When the inevitable waiting around becomes interesting.[*]When people are prepared to teleport or escort new team members, and once assembled there aren't any more transportation problems (I don't think moving as a group is that vital as long as everybody's safe and comfortable).[*]When I don't get the classic "You're not doing anything!" complaint against Dark/? Defenders. (Actually, it doesn't bother me; I genuinely love the unobtrusive nature of Dark Miasma, and my secondary has all the flash I need. But the comment still shows a certain lack of acumen.)[*]When I'm recruited to help run people's random missions and nobody is using an XPS (experience-per-second) meter or asking people to kick up their difficulty ratings. I'm fine with power levelers, but feel the average pickup group is better suited to playing while enjoying the added chaos or order your teammates bring to your life. Just meant that the tone of the group should be decided by the team leader or a majority, and everyone should know and be all right with it.[*]When I can say in my Looking For Group box that I explicitly don't want any experience points and can still find a suitable pickup group. (Okay, this hasn't happened yet either, but I can dream...)[/list]All in all, about the same things everybody else mentioned, although my standards are a bit looser regarding tactics. I have to echo the sentiment about no-communication synergy: spooky but exhilarating. And while looking at the bios doesn't always help (some of the serious alt-a-holics both are the most likely to understand the game from your viewpoint and the least likely to have given all their characters bios (or at least, will have edited all of them to fit in the space provided)), it's definitely the best single indicator I've found.
Just to add something a bit more original, though: sometimes it's actually more fun (and funny) to be in a somewhat dysfunctional pickup group. Especially if you want to do a bit more roleplaying than usual; when things are already pretty much hopeless, that means there's no pressure. I design my characters before trying to squeeze them into archetypes and powersets, and so have a number of in-character but suspect builds and playstyles. Sure, my clichéd "hypnotic anime schoolgirl" Dominator can function perfectly well Holding off waves of guards while a Gravity specialist cracks the bank vault - but since the character actually isn't the usual, most of the time she's more at home pretending to be a flipped-out catgirl, screaming, scratching and climbing all over the guards (and taking a beating doing so), with the inherent potential for physical humor... and when there are three beginning Masterminds and their out-of-control minions all over the place, that's almost a saner combat strategy than the cool, aloof standard. And it's nice to have room for my own Mastermind to indulge in his habit of assembling his monks (an Arachnos ninja faction that have somehow persuaded him that they're monks who worship him as a messiah) and preaching to them, sometimes in the middle of a fight (my private goal being to see how little I can seem to be fighting while keeping the faith-healing show going and "accidentally" helping with the ongoing struggle). Or a Corrupter who happens to be an former head cheerleader and current diva (at least in her own mind) who's constantly using Grant Invisibility to keep people from stealing her spotlight, Challenging various enemies and "blasting" teammates for imagined slights (she has no clue at all that her Thermal Resonance secondary is a support powerset), and doing the "talking on your cell phone with your girlfriends while mostly ignoring your surroundings" shtick. Wouldn't want to go that far in a normal pickup group, but once everybody's pretty much figured out that this team just isn't going to even resemble a "well-oiled machine", then as I believe an elevator in the Paranoia universe once said, "We hope to be ascending to the level of, oh, say the RIP sector parking garage. If not, well, we'll try for something else on the way back down."
I suppose the secret to a really good pickup group is for everybody on it to be looking for the same thing, or at least like what they end up with.
_____
I've often listened to my colleagues curse the monsters that interfere with what they consider the serious business of vendetta. Personally, if I must contend against my fellows, I'd far prefer to do so on some noisome plain crawling with beasties. I welcome all such distractions, when the alternative is to simply slaughter - or be slaughtered by - other [players]. - Kafkar.