Honestly, I do not blame him. His reaction became the staple reaction for today's programmers for when their program actually works somehow.

The book establishes that the reason Victor freaked out was because he expected the Creature to look like a perfect, Romanesque figure of a man, and instead he got something vaguely described as a walking, talking cadaver that had been left in the woods for a few weeks. It's less that "the thing he designed to be alive is alive" and more "he wanted the Terminator and got the Toxic Avenger."