The reason the ones with negative exposure compensation looked right is because your subject is dark.
Remember, the camera doesn't know what you're pointing it (*) or what colour that is. So it assumes that on average the scene is a sort of mid tone (18% grey). A polar bear in a blizzard and a black cat in a coal cellar both look the same to the camera. So you have to tell the camera what to do. You dial in positive exposure compensation for the polar bear to make it come out white instead of mid grey, and you dial in negative exposure compensation for the cat to make it come out black instead of mid grey.
(*) If you're using evaluative metering, the camera can sometimes work out the subject is; it can recognise that the subject is a face, say, or a landscape, and set the exposure accordingly. But for your photo I think the evaluative metering would have no chance working it out properly.