The human condition is that thing you just can't quite put your finger on about just why life sucks so much. You know that it does, and it does for everyone regardless of race, gender, religion, or culture. It is the "suck" in "life sucks."
Causes of the Human Condition
Why does life suck? Why are you asking me? What am I even doing here? Am I really here? We're all going to be dead at some point anyways. Why am I doing this? Why am I doing anything? Am I even really doing anything?
According to Christians, Jews, and Muslims
Life was perfect and things were generally just cheery and awesome. Humans were feeding lions by hand, everyone was naked, no one cared, there was no fighting - everyone seriously was just chilling. All they had to do was follow a simple rule. Don't eat the fruit of this ONE tree, dammit! Well, Eve ate it because a snake told her to. Adam then executed the longest, hardest facepalm in history. It was so hard, God heard the smack from heaven. In the interest of not having to spend eternity alone, Adam begrudgingly ate the fruit as well. From then on, man and woman were banished from paradise because of their mistake. They were condemned to live in this shitty-ass world where people will always want what they can't have, and people do terrible things to each other, and man can be free to feel superior to women because they weren't the ones that got us kicked out of the garden in the first place.
According to Nihilists
We are the way we are for absolutely no reason. We're just riding meaninglessly around on this little blue ball in the vastness of space. We have created all of our problems in our heads, so, the good news is, none of our problems actually are real.
According to Sperm Whales Falling Through the Sky
“Ahhh! Woooh! What's happening? Who am I? Why am I here? What's my purpose in life? What do I mean by who am I? Okay okay, calm down calm down get a grip now. Ooh, this is an interesting sensation. What is it? Its a sort of tingling in my... well I suppose I better start finding names for things. Lets call it a... tail! Yeah! Tail! And hey, what's this roaring sound, whooshing past what I'm suddenly gonna call my head? Wind! Is that a good name? It'll do. Yeah, this is really exciting. I'm dizzy with anticipation! Or is it the wind? There's an awful lot of that now isn't it? And what's this thing coming toward me very fast? So big and flat and round, it needs a big wide sounding name like 'Ow', 'Ownge', 'Round', 'Ground'! That's it! Ground! Ha! I wonder if it'll be friends with me? Hello Ground!
According to My Co-Worker, Garrett
Garrett: Dude, it's like, when you have skin and you are alive and your heart beats.
Me: But that is true for all animals.
Garrett: Ohh. Well, it's whatever makes us wear clothes and not take craps everywhere.