"Don't blame other people for disappointing you, blame yourself for expecting way too much from them." - Unspecified

Interpretation:
We meet someone, make friends, and finally begin to feel that amazing sensation because we 'seemingly' found our best-friend, we think they will never let us down. Little do we know that life's not that simple, as time goes on we begin to see their true colours, we get bored of them. We move on, meet new people; make new bondings and learn as we grow. Importantly oneself should learn from their mistake (mistakes shouldn't be constant.) We should learn to become less dependent on others. People come and go.