More people should learn from this attitude. This is what I say every time I have an idea, and I later found out someone already built a startup around it (happens quite a lot, since I spend half my waking time thinking of startups).
Indeed. It means you possibly have a head for good ideas. You should be far, far more worried if nobody else has beaten you to the punch on any of your ideas, because that would tend to indicate that your ideas are either impractical or of low quality.
