I'm sorry but in what world is improving the performance of the product you're working on 10 fold "bad" ???
Yes, it was probably a shock for the team. But those kinds of moment are also a huge opportunity to realize there was something wrong with the way you were working.
I've had a senior engineer erase the entirety of my code once in front of my eyes and rewrite it from scratch in a few hours, still in front of me. Well, i still joke about it with friends that experienced the same thing from the same guy, but it was definitely the kind of things that motivates you to improve the quality of your work.
Of course, the senior guy was a friend and it was all done with smiles and laughs. He didn't make it sound worst than it was.