Up to now, I haven’t disproven anything yet.
You might be surprised to hear that the most interesting result for a scientist would be something they didn’t expect. This usually means they haven’t understood. So then, they have to go away and understand it!
I make mistakes all the time. It’s not really disproving, more realising that you missed something and need to update a bit…. again and again. And in the end we make something good. That’s not just a science thing. This is maybe a bit easier for experimental scientists, though: we don’t have a huge investment in any one theory. Successful theorists tend to be smart enough to not have all their eggs in one basket either 😉
I’ve found that some things that I thought would work don’t work, but haven’t disproven anything major. Like @Meirin said, it’s exciting when a theory gets disproven because it means that physics isn’t working the way we thought. (might not be exciting for the theoretical physicists that came up with the theory though)