The weird Human Race

Blushing refers to the involuntary reddening of a person's face due to embarrassment or emotional stress, though it has been known to come from being lovestruck, or from some kind of romantic stimulation. It is thought that blushing is the result of an overactive sympathetic nervous system

kiss can express sentiments of love, passion, affection, respect, greeting, friendship and good luck, among many others
a kiss is a ritual, formal or symbolic gesture indicating devotion, respect or greeting

Goose bumps, also called goose flesh, goose pimples, still bumps, chicken skin, Dasler Bumps, chicken bumps, people humps, or the medical term cutis anserina, are the bumps on a person's skin at the base of body hairs which may involuntarily develop when a person is cold or experiences strong emotions such as fear, nostalgia, pleasure, awe, admiration and sexual arousal

A yawn is a reflex of simultaneous inhalation of air and stretching of the eardrums, followed by exhalation of breath. Pandiculation is the act of yawning and stretching simultaneously.[1]
Yawning is commonly associated with tiredness, stress, overwork, lack of stimulation and boredom, though recent studies show it may be linked to the cooling of the brain.[2] In humans, yawning is often triggered by others yawning

A sneeze (or sternutation) is a semi-autonomous, convulsive expulsion of air from the lungs through the nose and mouth, usually caused by foreign particles irritating the nasal mucosa. A sneeze expels air forcibly from the mouth and nose in an explosive, spasmodic involuntary action resulting chiefly from irritation of the nasal mucous membrane

Perspiration (sweating, transpiration, or diaphoresis) is the production of a fluid consisting primarily of water as well as various dissolved solids

A wink is a facial expression made by briefly closing one eye.[1] A wink is an informal mode of non-verbal communication usually signalling shared hidden knowledge or intent, which may also include, in all contexts, sexual attraction

Flatulence is the expulsion through the rectum of a mixture of gases that are byproducts of the digestion process of mammals and other animals. The medical term for the mixture of gases is flatus, informally known as a fart
farting is generally considered unsuitable in formal situations as it may be considered vulgar or offensive