I consider street photography as art and freedom.
I don't need high-tech equipment and I can do it anytime everywhere. For me it is the use of photography to capture my surrounding as I perceive and feel it. I watch people who attract my attention and try to find the right moment for the shutter. While walking through the streets I see details, shapes or objects that show lifestyle, culture, technology and are traces of human life.
Therefore it is not a must for me to have a human being in the picture. I think street photography can also show the circumstances and outcomes of human life.
My main motivation is self-reflection. I never start with a certain project. I walk with all senses open. When I focus on something, my concentration lies on the composition and contrasts of the frame. I press the button, normally once or twice, and go on walking. After a photo walk I am always curious what I took with me on the storage card. With Adobe Photoshop Lightroom or Snapseed and Photogene (on the iPad) I do the black and white processing and complete my vision.
Street photography teaches me a lot about my perception and perspective.