Why do phospholipids form a bilayer in aqueous environments?

In an aqueous environment, the hydrophilic heads of phospholipids are attracted to the surrounding water molecules, while the hydrophobic tails avoid water.

To minimize the energy and maximize stability, phospholipids arrange themselves into a bilayer, with the hydrophobic tails facing inward, shielded from water, and the hydrophilic heads facing outward, interacting with the water.