Extremely Angry Toddler
Toddlers are still learning to express their emotions, so it's not uncommon for them to throw a tantrum or get irrationally upset about something small. They are also very ego-centric - toddlers think that the world revolves around them and that's a completely natural and normal ideology for them to have. That said, having an ego-centric attitude means that when things don't go their way they will get upset. They don't understand why they can't have whatever they want whenever they want it. Paired with an inability to fully express their needs or desires and you'd be frustrated too!!