Why is it amazing that it left the pad?
SpaceX has no test facility capable of withstanding a full thrust booster test on the ground.
Also SpaceX has more boosters and ships complete and in various stages of assembly. A complete loss of the pad would have been much more damaging to the program.
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.