Are difficult interview questions a bad sign?

If the questions are hard or the questions are technical and you don't know it, he, or she's not doing it from a malicious place. They're just trying to know if you're the right for company. Previously, I thought it was a place to get to, it was way to finish a task and get to a particular destination but I find it an experience, because it makes me know myself much more and also the company that I'm being hired for.