True, but for car to move ahead - engine needs to be cleaned first of inner garbage (eliminating emotional pain and replacing negativity with positive personal attitude).
Once engine is clean - the car can move. Forward (aiming to help others) or backwards (trying to please oneself which cause accumulation of inner garbage again).
But to me, personal "maintenance" has more to do with introspecting on things are stopping you from moving forward as a person.
Intelligence and success, I think these aren't part of that maintenance. For example, I can think of many people that aren't profoundly intelligent and/or successful, but have a great impact on others, even society, and thus are very happy, positive people.
Once engine is clean - the car can move. Forward (aiming to help others) or backwards (trying to please oneself which cause accumulation of inner garbage again).