Mia is at the toddler stage when she doesn't get what she wants she cries or if she can't get the shape to fit in the shape sorter she gets frustrated and throws it. This happens to all kids and parents handle tantrums differently, but why do toddlers get angry when they don't get their way? Their emotions are maturing.
She is discovering that she has her own likes and dislikes, her own wants and needs. She is her own person and is seeking independence. The reason toddlers get angry over little things is because they are discovering they have emotions, but don't know how to control them yet. She also don't understand that what she wants now she may be able to get later since she has little understanding of time.
So here's some examples of things we do to soothe Mia's little tantrums. If it is the case of the shape that won't fit I pick up the matching piece and show her where it fits then she will get the piece she threw and put it in the right place and continue playing. If the fit is about wanting a cookie instead of dinner we move the cookies out of sight and she eventually forgets about it. Sometimes she throws a fit when it's time for diaper change and in that case we just give her a book or a toy to distract her. If she wants more noodles instead of her sausage for dinner that's an instance where we pick our battles and just give in.