If I'm being honest with myself, when I'm playing with strangers, my heal threshold is pathetically low (the amount of damage taken before I feel like I need to step in and heal). There's no point in risking a wipe when I don't know these people and who knows the fight/what buttons to push.

With friends? Yeah, I enjoy my power a little too much. In dungeons I let them sit at whatever hp till the next aoe burst goes out, and hit them with Excog/Dignity/Bene when death seems imminent. I mean, do you really know your tank if you haven't heard them grunt in panic over discord? I really know all my tank friends.