Tactful ways to inform people that they're playing badly?

[NessaWyvern]

There was a WHM in my lvl 79 dungeon, who kept using the LB as soon as the bar filled, even if everyone was at full health. I said "I don't want to be that guy, but the LB in dungeons is usually reserved for Dps " but I got no response (despite him talking earlier in the dungeon) and he kept doing it. He uses healer LB at one bar again a few more times with everyone at full HP, and since I was starting to get a little annoyed, I asked them "So, uh, is there any point in using healer LB when everyone is at full health?" still no response. Might not be the most tactful way of wording it though,but I assume it sounds better than "Stop wasting the LB, healer."


Since I wasn't sure if I was being trolled or not, I just blacklisted them when I got out of the dungeon, as they were on the same world as me. >. >

I wouldn't usually say anything, but this was a lvl 79 dungeon, and he's gonna get a lot of hate later from others if he keeps using healer LB as soon as the bar fills.