@Gilette Inches and degrees. Emotional reactions can be wholly unreasonable, for a variety of reasons. It cuts both ways, and I have seen (and on occasion BEEN) a person who needed to take a step back and take a deep breath, and didn't, at least not with the alacrity I should have. You live and you learn and on occasion, you err.
I have also seen people who viciously emotionally abused others by telling them they were too invested, when in fact it boiled down to them holding the other person by the wrists and making them slap themselves in the face, while chanting "Stop hitting yourself!"
Some people can be cool cucumbers. Some can't. The last time I lost a character, I actually found the experience liberating, like passing through a pitch-dark doorway and finding not a stone wall or a bottomless pit, but a multiplicity of choices on the other side.
But I can't really blame someone for not wanting to go through the door, especially not if there are other attached problems, which all too often there seem to be in these high-emotion instances.