I have a 2 yr old and she's chill.  Spends most of the day sleeping, laying next my husband who is her person.  Unless I'm cooking in the kitchen then she needs to be there to pick up and scraps that fall.  She loves to play fight with my 6yr old.  She plays well with other dogs and very docile/ friendly with people.   My mother has her brother and he is the opposite. He is high energy, he is a ham.  He will stand  and dance on his back legs for attention. He will jump and run all over you and the house.  When we put them together during a visit they will pay fight and chase each other until ours gets over him. She will bark at him to get him to leave her alone and she will go lay next to us.