Hornet
Hornet: How patient is your muse? Are they easily perturbed? What sets them off the easiest?
After centuries of dealing with people’s bullshit and time itself, Gaster has learned a fair amount of patience. Patience bodes better in the long run than recklessness or impulsiveness. He knows this and his tolerant, open personality make patience an easy virtue for him.
Now, he’s seen a lot and has been through a lot - certain things do still upset him, though mostly through nightmares.
What would set Gaster off would be things like bigotry or biased hate against someone (as in racism or sexism etc. etc.). He’s a very open-minded guy so it just doesn’t make since to him why people would act with such close-minded views. Insulting someone he loves is also a sure fire way to set him off.
(He also loathes it when people discriminate against whoever for being monster or human. Gaster loves both equally and is aware of the fact that both humans or monsters can be good or bad).