Improving your own performance isn't just an individual thing. Its symbiotic (''a mutually beneficial relationship between different people or groups'')
Improving in almost any area involves collaboration with others, the team, coach, specialists, friends etc.
When the individual focusing on improvement takes on the advice from the coach, the coach in return receives feelings of accomplishment and personal learning. This is in part, similar to what the Great Swiss Psychologist Carl Jung described as the ''Transference'' in therapy.
Going to the wider circle, the group (colleagues, friends family) they see and feel an improvement in growth from the individual, this ''rubs off'' on them as well. This is what Cesar Milan ''The Dog Whisperer'' calls the ''Language of Energy'' Have you ever seen someone come into a room in an aggressive manner, how does that feel? If you see another person come into a room with a genuine smile, how does that feel?
Personal growth benefits from collaboration with others and those collaborating benefit from it too.