Alexander Weiss, the co-author of the study, adds that the 500 middle-aged apes they studied aggressively went after "things that they want, like mating with more females, or gaining access to more resources" to compensate for the void in their sad, unrewarding, monkey life.
"I should buy a Ferrari."
Weiss theorizes that the unhappiness amongst primates is likely a common evolutionary mechanism: a kind of ticking time bomb of insecurity that amps up their unfulfilled sex drive, makes them hoard resources, and causes them to fight to enhance their rank within the group, all in the simple pursuit of elevating their reproductive chances before it's too late. If that sounds painfully familiar, maybe get off the phone with the Harley dealership and just surf Urban Dictionary for a while instead. It's cheaper.