Little kids have a lot of big feelings, ones that can change rapidly and dramatically from the time it takes you say "Would you like a strawberry jam sandwich?" to "Oh dear, we only have the ends of the bread loaf left." But they can't always express their feelings in words, so they often do so in tantrums and tears. Prodding from Mum and Dad -- calm down, let's talk about it, tell me about your feelings, are you upset? -- only makes them more frustrated.