Cohesion holds hydrogen bonds together to create surface tension on water where water particles will stick to one another.
Real World Application:

Water Drops: Water drops being stuck at the end of a pine needle and water drops pile onto each other until it gets too heavy and falls. They’re composed of water molecules that like to stick together.

Human and/or Global Impact:
Relationship to Chemistry: Cohesive forces are responsible for a surface tension, which is the resistance of a surface to rupture(burst) when it is tensed up. Cohesion is a natural property of a molecule, determined by its shape, structure, and electric charge distribution. When cohesive molecules approach each other, the electrical attraction between portions of each molecule hold them together to stick. Each water molecule can form four hydrogen bonds with neighbor molecules.
Relationship to Chemistry: Cohesion is what makes up a whole, without cohesion we wouldn't have full amounts of water or liquids or solids.
Relationship to Water Cycle:The water particles of the same substances stick to each other. Cohesion is important in the water cycle, because if you didn't have cohesion you couldn't make a drop of water since one drop is made up out of millions of molecules of water.