It's good to honor your commitments.
John promised Jessie that he would take her to the bookstore after work.
John wants to relax after work.
John asks Jessie if he can take a quick nap before heading out to the bookstore.
John avoids seeing Jessie and heads straight to bed, afraid to have to let her down.
Jessie doesn't mind waiting while John naps and makes a list of books that she wants to pick out at the store.
Jessie is sad and trusts John's word a lot less, feeling like he is unreliable.