It always seems to happen when you are already running on too little sleep: your arm or your eye starts twitching spastically, as if you weren't having a hard enough time concentrating.
The subtle jerks could last for two minutes, or two hours, but either way, it feels like an eternity.
These involuntary movements can be disconcerting, and have driven many people to the neurologists office, asking what is happening to them.
But, in reality, these pesky spasms happen to the vast majority of us at one time or another, and an expert explained to Daily Mail Online just what is going on behind your tired eyes.
Involuntary eye twitches may drive you insane the day after a short night, but a neurologist says you don't really need to worry about anything being wrong with your brain
'People get nervous about them but really, they're benign, not pathologic,' in nearly all instances, Mayo Clinic neurologist Dr Eric Sorenson says.
Indeed, forums like WebMD and Quora are chocked full of terrified questions about unnerving, jerking eyes.
These twitches are are a minor electrical miscommunication between the brain and the body.
There is an association between twitches and amyotrophic lateral sclerosis (ALS), which has probably caused a second sleepless night for plenty of people suffering the tired twitches.
But in reality, most twitches are normal and harmless, explains Dr Sorenson.
Scientists like Dr Sorenson describe these twinges benign fasciculation syndrome (BFS).
While it is technically a 'neurological disorder,' BFS is hardly out of the ordinary and will strike most people at least once if not periodically throughout their lives.
Nerve cells are like a battery. Every time it fires, not only does it discharge a pulse, but it has to be recharged, during the resting state
Dr Eric Sorenson, Mayo Clinic neurologist
These twitches are akin to what happens when you plug your phone