We all have a mental picture of how we look. This self-image is derived from our dressing / makeup mirror. Professional portrait photographers strive to duplicate this view with their camera. A few photographers naturally acquire this ability, the rest must practice and study and practice some more.
What I am trying to say, it’s only dumb luck if a selfie or a snapshot taken by a friend will satisfy.
The needed skills allow you to choose flattering camera angle and position, not to mention, flattering lighting. Bottom line – if a friend snaps a picture of you, odds are, you won’t like it.