When light falls on the face in a certain angle, certain scars become visible. Those scares can make the skin seem imperfect and can make the person look older.
Skin imperfections such as eye-bags, smile lines and forehead lines can become more visible based on the amount of light reaching the facem and the angle with which that light falls on the face. See why do people look bad in photos.
The intensity of the light is another factor that can make the skin look imperfect. Depending on the imperfections you have on your skin, certain light settings can make you look less attractive.
Strong white light can change the color of makeup. This could result in a totally undesired look if the makeup is applied in a different lighting. See why we look ugly in sunlight.
Each person has different imperfections in their face. Those imperfections can seem more or less visible depending on the angle with which the light falls on the face. See why you look different in different mirrors.
Strong fluorescent light can make most imperfections visible, and you might thus look very different if you look in a mirror that is located right below a strong fluorescent light. See why do I look ugly when I wake up.
If one side of your face gets more light than the other side, the 2 two sides might look different; thus making you look less attractive. See why do we find symmetrical faces attractive.
When light hits our bodies with a certain angle, the curves we have can become more visible. A person's belly might seem larger in different light settings and so the person can appear fat.
Light sources have an attribute called the CRI or the color rendering index. If the light source has low CRI, it might not reflect true colors of objects. This is one reason why fluorescent light can make people look less attractive.