Could be a sign of a lot of things, including severe stress, or emergency caring.
If a friend calls me for a ride… right after I got my car stolen… I’d probably be pretty temperamental with them.
If… after politely telling the children dozens of times not to play between parked cars, and I catch them doing it, I’ll probably be pretty temperamental with them, understanding that anger can often be the catalyst needed to sink an idea into someone else’s head permanently.