Why do people get pimples?
Humans tend to get acne and blemishes because of grease. Grease occurs because of the hormones in your body. As you may know, there is bacteria all over your body, some are good and some are bad. The bacteria on your face is some what good yet some what bad. The good thing is that the bacteria of your face eats the grease, making your complexion less shinny and greasy. The bad thing is, for people who produce a lot of grease, the bacteria gets full and has to "do its business" and the bacteria literally poops on your face, causing pimples. Therefore, answer to the question is because of growth hormones in a humans body, which cause grease, which cause pimples.
People who get pimples usually are people who eat lots of fast/greasy food. Such as pizza, McDonalds, etc. Teenagers often get pimples too, usually they can't control them because it's apart of growing up, it can be in your genetics to get more than other people too. Some people get them for no reason too, but normally not many.
Pimples are common during puberty, due to hormonal spurt. You do not look dirty, when you have pimples. Late teenagers go on thinking about the pimples only. Almost every body gets the pimples and that is certainly not a crime to have pimples. So do not go on touching the pimples and do not squeeze them. You look beautiful by smile of the face, even with pimples there on your face.