2 years ago I had a really aggressive badly behaved 3 year old. He pushed, hit and fought with other children. At 2 he was even worse, he even hit babies.
At 5 he is lovely. His behaviour is fantastic. He is polite and great company. We laugh at the same jokes. He very rarely gets upset, has very, very rare tantrums and can be reasoned with about almost everything.
I'm not trying to boast, just saying it gets better. 2 years ago I was at my wits end.