Today, right after I got home, I was just in time to see the first launch of a complete Starship being scrubbed. It was a tiny defect that stopped the whole event, but better that than seeing the whole ship fail to launch and come crashing down. Instead, we'll have a minimum of 48 hours delay, as the tanks need to be recycled.
And of course a lot could go wrong, since the first stage has thirty-three Raptor engines, of which thirteen are used to steer the first stage. On top of that, there are some six engines in the second stage, and they all need to be controlled.