Hell is a concept made up by some bishop in the ancient world who wanted to control the masses and use it to threaten people into what he deemed as "societal normalcy" by holding the threat of infinite years of torment over their heads if they didn't follow his specific interpretation of his specific creed of magic space voodoo, and it caught on.
...Wazzat? This isn't a question on the actual nature of hell, but rather what our personal hell would be like if it was real? My bad!
Hell is having Gastro or food poisoning every day for all time (seriously, one day of gastro last year fucked me up so bad I thought I was gonna die).
Hell is being forced to relive high school as the outcast-loser-ADD-Mildly Asexual-wuss, and everyone else is either a jackass jock, a sociopath whose uncle is the VP of discipline (and thus he gets away with everything), and they're all testosterone-happy-gorrilas who mistakenly thing you're a "sissygayfagbitch" and throw you into garbage cans, ostracize you in every manner possible, and deliberately try to hurt you in gym class and then go "Oh, I didn't know basketball was a non-contact sport, herp derp, besides I think Aegix threw himself on the ground on his own because he wants me in trouble because he's a teacherspetlosertattletaler!"
Hell is being stuck doing shitty complex math courses you don't need in University and then finding out that somehow they don't count or you're otherwise forced to repeat them, and other courses you hate, ad nauseum again and again and again and you wonder if you will EVER fucking get out.
Hell is seeing Trump shove aside the notion of consent in public, and then turning around and seeing everyone in the room with you agreeing with him. (Have not experienced this, although I'm seeing rape apologists and excusers pop up everywhere online in the last 3 months and I'm getting really sick and tired of it)
Hell is your computer constantly going "there is a problem!" and not giving you any details and you're desperately trying to make it work so you can turn in an assignment and you realize your last backup was months ago.