Healer will get the blame most of the time. One tank to me went: "Oh, sorry, I didn't realize you were undergeared for large pulls." I was like: "Oh, I'm sorry, we didn't have an aoe DPS and you expected me to heal you through all that?" Tank goes: "What do you think a BLM is?" I went: "Oh, sorry, I didn't realize you couldn't pay attention to the fact that the BLM was afk and not here." (You'd think the lack of big explosions would've been a clue?) Party (amazingly) actually agreed with me and went: "BLM was afk at the time." Even the BLM admitted to it. (Tank was not happy with us). Next group, tank lost aggro on the mobs and so I ended up letting him die to save the rest of the party. That is what I consider a GOOD run.
A great run, there is no problem, tank does their job, holds aggro, checks to make sure the party is ready, makes sure that when someone goes afk, they change their strategy accordingly, lets the healer who is doing the dungeon for the first time know what they are planning...
A bad run? It ends up with: Healer, why didn't you set the bomb? Healer, why didn't you heal me (despite being attacked by every enemy). Healer, why didn't you... Healer, you need to... etc.
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Now, for the OP, I agree with most of the post. However, I slightly disagree with:
2) the going into new areas part. I've done that plenty of times and survived. The problem is knowing when you can and when you can't. Example being the guildheist with the bomb goblin things in the gri forest area with that big root leading up. I run ahead all the time there because I can rush ahead, start nuking the goblins before even breaking the barrier, and boom, can take our time taking out the barrier at our leisure.
3) Aggro. I've forced aggro onto myself (thm) (generally with the healer knowing not to heal me unless the instance was so low level that it didn't matter) when the tank was undergeared and I was actually reasonably geared in order to reduce burden on the healer and tank (I'd take maybe 1-2 mobs and heal myself through, tank would take the rest). In other times, as an arc, tank was so bad at holding aggro that I used my tank pet to hold aggro on the mobs.
4) If tank isn't going after the mob, I will "break rank" to save the healer. Especially since the healer job is hard enough without being attacked. This ties in with 3.
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For when people don't talk, I will generally assume that they are on ps3/ps4 with no keyboard. even then, if the party is clearly waiting for you to speak up, even without a keyboard, you should try to type something like: no kb