Perhaps one of the most difficult parts about holding down an average job is the frequency with which you have to lie to maintain employment. Why do you want to work here? Can you be a team player with that coworker? Do you enjoy this job? All of these are questions that a significant proportion of the working population would find difficult to answer with complete honesty without HR somehow getting involved.
Needless to say, this creates a desire among many employees for a means to let off that work-related steam. This is where the likes of work memes come in, creating a safe space to vent that has the added bonus of being funny and entertaining. For every time you have to bite your tongue or stop yourself from rolling your eyes in the workplace, there is a silly meme that can be used as an appropriate outlet for those work-related woes.