It's a giant shaking and trembling structure built in a fail-fast iterative manner using unexpected materials (stainless steel) and processes (regular welding). Assemble all this in history's largest rocket ever, and expect everything to go perfect the first time?

I wouldn't have been surprised if the whole thing shook itself apart on the lift pad and blew up.

I don't know about you, but when I rapidly build and assemble large complex structures like a cowboy, I certainly expect a ton of failures on my first trials. When stuff goes much further than I expected, I'm in awe and disbelief.