Water, despite its ability to dissolve hydrophilic substances, is a poor solvent for hydrophobic molecules (such as lipids). I think, in general, water is effective at dissolving ions and polar molecules but not so good at dissolving nonpolar molecules.
Because the opposite regions of electrical energy attract water molecules, polar molecules dissolve quickly.
Because nonpolar molecules are more attracted to themselves than water molecules, it is difficult for water molecules to attract them.
