Thanks for all the replies! After some tanking on Qarn I realized how hard life as a tank is. Need to watch aggro, need to damage.. need to interrupt and place monsters' AOE away from party.. But is it really just situational? So far my perception has been that I have to keep all CDs up (for example, maim) while tanking and keeping an eye on interrupts as well. How "perfect" am I required to do stuff? Must I keep all my offensive CDs on while tanking or as long as the threat holds it is alright? Won't people be disappointed at my damage output if I forgot a maim here and there?

Another thing, which macros would definitely make your life easier?