I don't know about you but without sleep I'm not a pleasant person. The last time I slept well consistently was circa 2012 so I'm thinking I've been kind of an asshole since then? Seems about right.
But in all seriousness, sleep deprivation affects everything. Just staring at this screen trying to type and I feel the mush in my head, formerly known as my brain, working overtime, trying to make sense of what it is I'm trying to write. It's working at about 20% capacity as I slept about 2 hours last night.
One thing I believe to be detrimental to health is lack of sleep. I function optimally with about 6.5-7 hours. It's not a lot to ask but rarely is it attainable, mainly as a result of my lifestyle choices (aka blogging) and also based on the unpredictability of young children's sleep.
Sleep deprivation makes for shitty days. But I'm told it gets better as kids get older. Whoever you are that told me that, I hope you're right...