I normally don't commend ppl for playing their job, tank for tanking, healer for healing etc. It's their job and it's expected from them to do so. I did observe though when I'm healing and my tank doesn't bother to use any of his cooldowns and is getting hit like a boxing bag and almost dead every pull, I won't get any commends. On the other hand, when my tank uses his cds and allows me actually to dps, I will get commends. Also when I'm on smn and help the party by res'ing when healers are dry and E+E when it's up I don't get a single commend, even though I didn't just stand there and spam Ruin while my party was dying around me, which is something I hate seeing on other smns. People don't bother to see the bigger picture and analyze who was playing with their team or who didn't.

I will commend when I see:
1- tanks on low dungeons clearing all rooms, using their cds, going for adds when they OT, watch for the party's enmity.
2- healers who esuna when needed (god what is it with healers lately? do they have to pay for esuna/leeches?) and not just cure when there's a dot to be dispelled.
3- smns who resurrect without having to be told, send their egis to adds that need to be killed asap, e.g. portals on WoD.
4- blms who apocastasis weakened players during a major aoe and.
5- any dps who doesn't ignore mechanics and adds to stay at top for parser on the boss.
6- anyone who plays with the party, not an offline game that happens to be connected to the internet

I won't commend if I see:
1- lazy tanks, no adds, no cds, penis comparison at bosses.
2- healers on medica2 spam, no esuna, keep dpsing when players need to be healed
3- any dps who just plain ignores everything, doesn't dodge even if you bribe him to, no ballad/requiem/goad/heavy thrust/flare at full mp
4- anyone who just looks for his own penis enlargement, stressing the rest of the party