Aside from running with guildmates (which by the way does absolutely nothing to help communities)
spamming chat channels (at least at that time there was a dedicated world LFG channel)
lie about their specs
whisper random people in hopes they're a healer or tank, aggravating them with begging, and surprise, ruining the community.
So all in all, engaging in obnoxious behavior that in real life would equate to public intoxication, disorderly conduct, indecent exposure, take your pick of an analogy.
If you guys have "friends" or "guildies" that are willing to play when you want to play, fantastic, go play with them. If they ditch you for a dungeon finder, that means you weren't a desirable friend/guildy to begin with.
Let the rest of us have a choice.