Electrostatic Potential Energy

[Sofia Cerpa 2E]

for values of electrostatic potential energy, how come two positive values are repulsive while one negative and one positive value are attractive? is this because of the stability of the negative values?

[Ryan Blaydon 1K]

I am not exactly sure the reason as to why 2 like charges are repulsive and opposite charges attract. I do know that this is based on Coulombs law which is just an experimental law of physics.