Irascible

[Raeanne Dimick]

a word used to describe a person (often a coach) who, on the surface, is easily provoked to anger or very irritable but who everyone knows, deep down inside, has a heart of gold and a warm glow of support, appreciation, and kindness. The phrase is often used to describe Michael Mickey Goldmill, who was a fictional character created by [Sylvester Stallone], portrayed by [Burgess] Meredith in [the Rocky] film series, and who, while often very irritable had a heart of gold and always wanted the best for the kids.

[Vania]

Having or showing a tendency to be easily angered.