Tennis can be therapy for those looking for an escape, a safe and pleasant one. I used it for that while growing up. Tennis can be the means for achieving the habit of discipline that will carry over into other aspects of life such as work and gaining an education. For me, it was a way to take away all of my concerns while focusing on simple elements as movement, concentration, and conditioning. Later, when I began teaching, it took on the further concept of analysis. Learning to figure out why one thing works while another does not is central to any skill, art, or discipline. Learning and teaching tennis contains the same challenges to both body and intellect.
Why teach? Simple reasons such as I prefer to work outside in the sun, I like to exercise, I like coaching, and I love teaching others how to play Tennis.