Here’s my same answer as in Twitter, but with a little more depth.
By “learn”, I mean learning about a product, how you can use or abuse it, and give feedback in order to hopefully make it better, in some context. I have used this line almost exactly in interviews, while being surprised at how many people hire for testing roles knowing nothing about testing. (Side note: it usually gets very positive feedback from interviewers)
“Making mistakes… on purpose” is my light hearted answer to casual conversation, especially right after I mess something up. “That’s my job!” Then if someone asks for more, I explain that a part of what I do is to think about what people will do wrong with my system and do it myself before they have the chance to do it.
“Program” is what I typically tell people when they ask what I do and I don’t want to explain the use of testing. It isn’t technically wrong, since my current job is as a tool-smith and test automation “expert”.