Imagine having your mother touch your cheek. Then imagine having your spouse or someone you love romantically touch your cheek. Then imagine having a baby touch your cheek. Then imagine having someone you hate and fear touch your cheek. They're very different feelings, aren't they? They all involve the same nerve endings, stimulated in basically the same ways, but with emotional content that varies to every point of the compass. This is because the sense of touch communicates and actually conveys emotion, communicates and conveys love (both good and bad) between people. That's why the Lord so often touched people as a way of healing them; through touch he could convey His love, which is life itself, to the people he touched. It's also why the people of Israel were not to touch the Ark of the Covenant -- their base loves would be conveyed to the holiness represented by the Ark.