And the game gets easier. There are three spells you have to watch very carefully -- well, two spells now. They were Starfall, Force of Nature, and Typhoon. Each of these had the ability to aggro outside of what you were intending to DPS and had to be used very carefully.
Treants will often pursue new groups of trash if you forget to tell them to stop and follow. Starfall would aggro *anything* nearby, which, honestly, was great for the Fireland dailies that require smashing charred mobs. Typhoon travels a ways, and tends to aggro things that seemed to be too far away... or yellows you forgot to factor in. An unglyphed Typhoon is even more difficult, as you sometimes had to make sure you didn't push mobs into the wrong areas. Touchy tanks hate typhoon pushback as well. Both are occasionally reasons to line up to the side of the mobs and Typhoon them into a wall if you're unglyphed. (I really enjoy Typhooning mobs into walls for some reason.)
Anyhow, apparently it's time to strike Starfall from the list of spells that require skillz. I used to be overly careful about using it, as I've accidentally pulled some trash, especially in Grim Batol, with SF. But now, well, SPAM AWAY!! (I'm on a trip right now or I'd check it out.)
Patch 4.2 hotfix roundup:
Starfall is no longer hitting targets that are within 40 yards if they are not in combat with the druid or his/her party/raid members. It is targeting all hostile characters in combat with the druid's party/raid members, is not hitting Stealth characters, is not breaking crowd control effects, and is not targeting nearby critters.