Seriously, if it care isn't taken you will have migraine all day which will affect your day's work, you won't be agile or fast with your work, it's going to be obvious to people that something is actually wrong with you.That's for sure. Not having enough sleep is bad for health. It would give you a headache and you will find anything irritating.
There are times that I don't get the amount of sleep that I wish to get. I want 8 hours but I only get around 6 hours, which I suppose is good enough.