Did you know not performing as you think another player should in a group

[magnanimousCynic]

snip

So you're OK with a BLM doing nothing but Scathe? What about a DRG that does nothing but Auto Attack and Jump? A RDM using exclusively melee combo? A SMN using Titan-Egi while only spamming Ruin II?

Because all of these examples have personally happened to me before in my years of Leveling Roulette. Should I have let them stay in the party even though they're likely doing <10% of the DPS that they could've done with a normal rotation?

And don't say something like "it's hard to tell what the DPS are using". If they're a caster you can see almost everything they do by the cast bar or the flashy animations. If they're not a caster then watch their animations and MP/TP bars. Is it going down at a normal pace? Is it nearly or always full? Is it nearly or always empty? Are they using critical buffs for their class like BRD songs? Are they using AoE for large pulls?

When I heal I can tell what my DPS are using a majority of the time. If I clearly see them not contributing a passable amount of DPS to the group I speak up and ask "DPS, you should try to do X, It will help you do more damage." If they use the advice and use it in the duty I don't say anything else, unless needed, and give them the comm. If they complain to me or say they're too lazy then they're getting the boot.

There's a difference between not doing a great job and trolling the party by not putting forward any effort.