Another pitfall with this approach is when someone has constant emotional but irrational reactions to everything. Being the person who validates their emotions becomes harmful if they’re over-reacting or developing harmful emotional reactions and you’re always there to validate them.
If it becomes damaging to you (the person that is expected to be emotional support), "grey rocking" is the next step. Acknowledge, but don't respond. "uh huh" instead of "I am so sorry" or whatever. Don't take advice from me though.
> someone has constant emotional but irrational reactions to everything
What are "emotions" if not "irrational chemical reactions in our brains"? Seems really strange to decide what it or isn't "irrational emotions" for someone else to have.
I, just like you I presume, see myself as a rational and logical person (maybe you're also a programmer), but I also realize that humans are humans, and having irrational emotions is very much part of being a humans, and emotions in general is such a subjective experience.