Astronauts must be nervous stepping onto the first manned flight of a new craft that has a 100% success rate in the sole previous flight, but might have only a 50% success rate by the end of their mission...
With both Crew Dragon and Starship, there will have been _many_ successful missions involving un-crewed variants of the spacecraft (Falcon 9 and Cargo Dragon were both well-proven systems before crew was a possibility).
Well at least they would have no one else to blame but themselves. As far as I remember it was the pilots that insisted on the shuttle to be not be 100% automated, so they had to do it this way. The soviets just made the whole shuttle automated so it could be tested without risk to crew.
With both Crew Dragon and Starship, there will have been _many_ successful missions involving un-crewed variants of the spacecraft (Falcon 9 and Cargo Dragon were both well-proven systems before crew was a possibility).