Everyone needs to feel they are special, that they are loved. This is a good beginning. Knowing that Jesus loves me can be some very powerful words through the tough growing years to come. If the child is taught this concept early, it will remain with him even through the difficult times. Jesus is happy when I obey my parents and play well with others.
Toddlers can learn the difference between happy and sad.
They know when they do something that does not make Mommy or Daddy happy. Young children learn to play nicely with others. When children can relate these concepts to what they know, real people, it makes sense to apply this knowledge to Jesus. Let children know that they can please Jesus. Name things that make parents happy and tell them these things also make Jesus happy.