Kissing is a very intimate act, and not something that you would usually do with a stranger or someone that you do not like. There are numerous kissing quotes that detail the joy that this act can bring, and also the sadness that it can be associated with this action. When a loved one passes away it is common to kiss them goodbye, and teenagers may view kissing as something pleasurable and stimulating. The act of kissing can be friendly or passionate. In Europe a common greeting is kissing the other person on each cheek, and many children expect a kiss before they go to sleep at night. There are some diseases that can be spread through kissing, and these can be mild or severe depending on the situation and the microbes involved.