What's a common misconception about angel investors? For me it's that they will spend money for nothing in return, so wondering if that's true or not.

I don't know, I'm told that "seeking out angel investors will allow you to have low interest to no interest loans", or even to the extend that "they will gladly give you money for good ideas, because they are philanthropists". But is that true? Or is the the myths of the ignorant?