Hard answers that explain our fascination with the oddly satisfying may be lacking, but one possibility is that it taps into our subconscious urge toward what psychologists call the "just right" feeling.

It's the sensation that arises when we've put things in order and serves as a useful cut-off point for simple tasks. It's also what often goes wrong in individuals with Obsessive Compulsive Disorder (OCD)—for reasons not fully understood, some people with OCD don't interpret the sensory cues that indicate the job is done, leaving them searching fruitlessly for a sense of completion. The quest for finality often leads to things like continually rearranging objects and repeatedly checking doors to see if they are locked.

In fact, OCD was the first thing that came to Sarah Keedy's mind when the director of the Cognition-Emotion Neuroscience Laboratory at the University of Chicago first viewed an oddly satisfying compilation.

"It was nothing I sat around and thought about, it hit me right away," Keedy said. "It was truly an overwhelming sense of this is a series of visual depictions of things that struck me as rewarding experiences that … [people with OCD] tend to be going for to a pathological degree."

Nuts and bolts that fit snugly together appear to satisfy an existential longing.

In a world of chaos and inelegance, it can be reassuring to see order. If anything, this content reveals that people with OCD aren't anomalous in their desire to bring a pleasing equilibrium to their lives after all.

The oddly satisfying sweet spot was famously examined by researchers from Spain. They gave people with OCD and a control group a word recall task and cut them off in the middle of completing it.

They theorized that a task involving ordering and checking something (in this case, words) would activate their internal "just right" sensors. Stopping them before finishing would then trigger unease.

The hypothesis was right. People in the control group felt uncomfortable when something was left undone, and for the OCD participants, it was even worse (two of them even mailed completed lists to the researchers afterward to satisfy their urge for finality).

The researchers' findings are hardly groundbreaking; of course, we do not like to leave tasks unfinished.

But extrapolating this idea to the oddly satisfying images, it's quite clear why seeing a plant perfectly peeling away from a building gives us so much satisfaction!