Water is a polar molecule, composed of two hydrogen atoms bonded to a single oxygen atom.
Water molecules like to stick to one another, like small magnets.
This is called cohesion. Water molecules also can be attracted to other substances, such as metal or dirt, especially if they have some static charge on them. This is called adhesion. Lastly, some substances are not at all attracted to water, and even repel it. When water falls on an unwaxed car, the forces of adhesion are almost as strong as the forces of cohesion, and the water spreads out.