Few stock photos have been reused as many times, for as many different purposes, as this one. The distracted boyfriend meme format takes a simple three-person photo and turns it into a flexible template for expressing a shifting preference between any two things.
What the photo actually shows
The original photo features one person looking back at someone new walking by, while their current partner reacts with visible disapproval. Meme creators label each figure with text, turning the literal scene into a metaphor for choosing a new option over something already familiar.
How the labeling structure works
The person looking back typically represents someone tempted by a new choice, the person catching their attention represents the tempting new option, and the disapproving figure represents whatever's being left behind or abandoned in favor of the new thing.
Why this format became so widely used
The photo's clear three-part structure made it endlessly adaptable — almost any situation involving choosing something new over something familiar can be mapped onto these three roles, which is exactly why it's been reused for such an enormous range of comparisons. 
A black and white cat with a mustache is looking at the camera with a caption that says... — view on SoundGIFs
From serious to completely trivial
This format gets used for everything from genuinely significant life decisions to entirely trivial personal preferences, applying the exact same visual logic regardless of how serious or silly the actual comparison is.
Why the format has such staying power
Unlike memes tied to a specific event or trend, this format's flexibility means it never really goes out of style — any new comparison involving shifting preference can still be mapped onto the same three familiar figures.
Similar reusable meme templates
This format sits alongside other endlessly adaptable meme templates, similar in spirit to how what does caught in 4k mean gives people a flexible, reusable way to frame an entirely different kind of moment.
Conclusion
The distracted boyfriend meme format endures because its simple three-person structure fits almost any comparison imaginable. For more meme formats and internet slang explained clearly, browse SoundGIFs' full News section.