Ignoring the fact that “five minutes” was probably just hyperbole, you can absolutely get what you came for in five minutes. Five minutes is long enough for me to validate an idea from “wouldn’t it be cool to do X?” to “man I really don’t want to do X”. And I’ve just gotten what I came for, validating (or invalidating) an idea.
Just because you have an idea doesn’t mean it’s worth pursuing that idea, especially if it turns out you’re not interested in that idea after all.
I think this is a pretty important point. Often times I think I'm interested in doing something or I like the idea of it, but it doesn't take me very long to realize that I'm completely disinterested because of the actuality of the thing. I'm OK with that.
I think the parent is probably trying to say that you definitely haven't done enough exploring on most subjects in a short time to find and glean all the interesting bits, and I agree with that as well. There are work projects that I would have abandoned long ago if they were personal projects that I have got A TON out of by sticking with them and working on them for years. But in those years there has been a lot of slog as well, and it's probably not the optimal way to mine all the knowledge nuggets...
Just because you have an idea doesn’t mean it’s worth pursuing that idea, especially if it turns out you’re not interested in that idea after all.