Learning Basic Social Skills
Though your toddler mostly seems interested in what you can do for her -- like refilling her sippy cup right this second -- a recent study showed that kids as young as 18 months do recognize and care about other people. To encourage her:
Be proud of your own selflessness. Talk about your good deeds so your child understands what you're doing and why. For instance, explain to her, "I'm going to let this man go ahead of us in line because he's in a rush and we aren't."
Nurture your child's nice instincts. When she does something kind for another person, give her a great big thanks. A little recognition will encourage her to keep it up, and eventually she'll enjoy doing good without expecting anything in return.
Let it go. It's okay if she doesn't want to share her favorite toy with a new child at the playground. No toddler can be selfless all the time, and in some situations, pushing her will only make her push back harder.