Ugly can be defined as a person, place, animal, or thing that is found unappealing or unattractive by some or sometimes the majority of the human population.
Scientific studies have found that some things that are universally seen as unattractive features in people are:
-Asymmetry in the face. Which usually hints at underlying genetic problems. Applys to men and women
-Obese men and women and overweight men and women. (In some cultures being overweight is viewed as attractive because it suggests that you come from a wealthy, healthy family. But obesity is almost invariably viewed as unappealing.)
-Also, people with unnnaturally LOW as well as high amounts of body fat are usually considered less attractive than average weight people. Applys to men and women.
-Visible physical deformity and disease are always considered unattractive. Applys to men and women.
-Bad posture is a less serious problem but it isn't attractive in both sexes.
-Women with abnormally high levels of the male sex hormones such as androgens will have facial hair or acne, which is considered unattractive.
-In women of Western culture, short, flat, or lifeless hair is unattractive, whereas the ability to grow long, healthy hair is considered a sign of good health. The same goes for your nails! So no nail biting!
-Men of shorter stature may frequently be viewed as less attractive.
-Red hair is sometimes, but not always a sign of undederlying genetic or health problems. In cases of malnutrition, dark hair may turn blonde or red. Also, Ehlers-Danlos Syndrome, Type V, is a genetic disease associated with hyperextensible (loose) skin, mild scarring, mild tissue fragility, and hemorrhaging and is only seen among red-headed people. Red haired people often have pale, sensitive skin which is more susceptible to skin cancers. Although, to be fair I'll add that scientists have suggested that the vividness and rarity of red hair may lead to it becoming desirable in a partner and therefore it could become more common through sexual selection.
Soooooo. After reading all of this, it's clear that "Having a flat chest and big nose." or "Having pale skin and a flat butt." As other people have written here, does not make you ugly. Your body actually has natural instincts that tell you to stay away from certain physical traits. Big noses, pale skin and flat chests are not included in these instincts. People just believe this because immature little teenage boys and girls like to tease when actually they have to clue what they're talking about.
Immature Pubescent Boy "Man Ashlee Simpson's So Ugly Man, Her Nose Is So Big!"
Person With Common Sense "And Your Pubescent Acne And Little Man Boobies Are Sooooo Appealing."