She is 3.5 and has been with me for just a month now, but Im finding her a bit hard to deal with. She pushes my buttons for some reason. Specifically, she seems to enjoy annoying or hurting other children. She will hold something out of arms reach and taunt another child with it, jumping around laughing. Or push her baby sister over and laugh when she cries. Or hold baby's hand/arm too hard so it hurts. Again, thinks its funny. Today her and another boy had an argument over a toy and he snatched it, so I asked him to give it back. So she jumped around waving it at him laughing. Drives me mad. Perspective needed please!!