You don’t want a poker face! You want to be very expressive. But voice is even more important. Pitch voice soft and a little low, and always decreasing at the end of a sentence, the opposite of asking a question. Like a kind parent talking to a tired toddler or particularly stupid dog.

You’re trying to slip information into the person at a subconscious level, and the information you want to slip in is that you, the speaker, are trustworthy and will take care of them. It’s much easier to do this than to actually figure out and fix whatever bullshit problem they’ve created for themselves.

Note that this is not effective on people you see everyday, as they will eventually realize you didn’t do anything to actually help them. But for one-offs, work associates-of-associates, clients you’re not the sole contact for, and the more distant sort of relative, it works pretty well.

It takes too much energy to have a good poker face, I’d rather just stay grumpy.