No life is perfect. We have dark moments and happy moments.Life is made up of many moments. Many pieces ... like a kaleidoscope.
The appreciation we have of life depends very much on our way of dealing with what happens to us. How we react.
Our attitude toward life determines also the things we're willing to do or not.  I read that people who think they have better luck often see things that others pass by
Well... Sometimes just hearing someone say that we must be positive, cause negative feelings, especially if we are experimenting  a tough time. But our attitude is important, since our body and spirit are related.
It is therefore important to learn to have positive feelings.Gratitude, generosity, etc..
The feelings are contagious. 
A smile gives lots of smiles. A person in a bad mood can create a climate of irritation.
You have to surround yourself with positive people and things. This does not mean we are always happy. But our attitude will help us through difficult times.
And motivation, inspiration ... we need them.
These videos I have collected are those that give me energy when I need it. A smile, a thought, a melody that makes me happy, and so on.