I have to agree with Moonblaze. For example, take this mediocre painting:



This gives the impression the girl is looking away from something. The object the girl was looking at the moment before is not visible. This is obviously bad practise, as it gives a great feeling of emptiness. It also makes the painting look only half-done. I advice that in the future you keep expanding your paintings until there are only people looking at each other left.

A few other examples showcasing this terrible mistake: