Re: Putting the Shatner "ego issue" from TOS to rest
Another element that hasn't been brought up in this discussion, Shatner owned a small percentage (5%?) of TOS, so much of his on-set behavior may have been from the pressure of having a personal stake in making the show a success, critically and financially.
Dr. Howard, Dr. Fine, Dr. Howard: For duty and humanity! --Men in Black (1934)