How do you yell at people through chat?

I get more people use it incorrectly than ppl not knowing about it
The other day I had a Tank in the 81 dungeon use LB1 as their personal cooldown(ofc they didn't use cd's like rampart etc, but they could find the lb button)
We asked him nicely to save it for the dps but he just didn't want to listen.
Theres just a portion of people that doesn't want to learn or cummunicate in FF14, if you make it more clear there will still be people ignoring it, not aoe'ing etc.