…is practicing a solo concerto*
non-musician: wow ! that was really good!
me: are you kidding me that was disgusting.
This is such a common thing. We do something, get a compliment, and proceed to explain why we weren’t any good. This isn’t the way to reply.
Here … here is the reply you should give:
Thank you very much!
It’s easy. Practice it in front of a mirror until you get it right.