He who covets what belongs to another deservedly loses his own.

Attention fixed on what someone else has is attention taken off what you have, and the second loss usually happens before anyone notices. The garden goes untended while you look over the fence. Whether or not the outcome is deserved, it is reliable.

When envy shows up, use it as a pointer and then put it down. Name what you actually want from the thing they have, and ask what tending your own patch would look like this month. Then spend the hour there instead.