She is probably very uncomfortable and that is her way of dealing with her feelings. Also the yelling is probably hurting her and not helping. It is important for the adult to stay calm otherwise you cannot expect a child to stay calm. They take their cues from you. 2.5 years old is not old enough to be manipulative or intentionally mean as some people may think. She just needs clear boundaries enforced in a calm manner, and empathy. It is hard to be a toddler and always told no and can’t have your way. Try to see it from her point if view.
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