Kissing does seem a little illogical, but it has its benefits.
(1) It reduces blood pressure. Passionately kissing gets your heart going and your blood vessels dilated, allowing more oxygen to get to your system.
(2) It reduces headache and menstrual cramping. After an extended period of kissing, the dilated blood vessels can help soothe the pains of cramping.
(3) It helps fight cavities. Kissing gets the spit flowing, which washes away germs.
(4) It makes you feel good. The chemicals released from kissing are linked with feeling relaxed, reducing stress, feeling warm and fuzzy, etc (some of my own knowledge of the listed chemicals was added here).
(5) Kissing burns calories. A passionate kiss can burn 8-16 calories if you're fully engaged.
(6) Kissing boosts self-esteem.
(7) Kissing can tone the facial muscles that start to sag as you age, giving you a sort of face lift.
(8) Kissing can be a good barometer for how sexually compatible the partner is.
It allows you to share germs and build the immune system.
HOPE THAT HELPS