My DD is 3, but turning 4 later this month.
She is going through a testing phase at the moment, and getting very upset if she cant have things exactly her own way. On average she probably has about one tantrum a day, even if she is delightful for the rest fo the dday.
She is my oldest and i sort of expected the tantrums to have disappeared by now, but she works herself into a terrible stae.
Just after some ideas really.