Utterly Mad

Humans are constantly conditioned almost from birth to regard lethal violence as valid entertainment, and are taught to revere those who choose to kill other humans as a career.
Note that the very first technological innovations of humanity were ways to more efficiently kill other creatures.
We make harmless versions of weapons as toys for children.
We drink poison too, and derive enjoyment from the temporary malfunctioning it causes in our higher brain functions. The higher the toxin level the greater the beverage; diluting the toxin with water is severely frowned upon.
We poison our air and water to weed out the weak. We set off fission bombs in our only biosphere. We nailed our god to a stick. Don't fuck with the human race.
Humans cook their food by blasting it with microwave radiation
They metabolise a variety of corrosive gases, their process of reproduction is lethally dangerous and their respiration and food orifices are combined in such a fashion as to almost guarantee suffocation by misconsumed food articles. And that's not to consider the damage done to their spine and musculature by an inexplicable instinct to balance on the hind legs.
We take our own violent nature, and turn it into entertainment. Action movies, violent video games, even sports like martial arts or fencing are all derived from actions which, in the end, are intended to end the lives of sentient beings. and we enjoy them in our spare time.
We roll POISON into little cylinders and SMOKE IT TO RELAX!
We also want our bitches, if it has a hole or a vaguely phallic proturbance someone somewhere will fuck it.
Even our cows, which we eat, are FUCKING MONSTROUS. An alien will shit himself if a cow moos at him, it's a fucking 500kg slab of muscle and fat, capable of crushing a man to death. We made an industry of killing , eating, and using their bodily remains
Humans breathe oxygen, one of the most poisonous materials in the universe. It's the same fucking thing that makes FIRE. It fucking kills METALS, and we need it to BREATHE.
I mean think about it, we are constantly fighting for EVERYTHING, its our default method of interaction with other creatures, and we ARE slowly killing our planet, because we so THOUROUGHLY made it our b1tch
Humans are a proud warrior race with a pantheon of bloody gods: Rambo, Schwarzenegger, ect.

Human beings can sustain damage that would kill a wild animal. A broken leg for most wild animals is a death sentence, for mankind it is a painful inconvenience, even losing a limb entirely was just a more permanent inconvenience, and most of this (non-permanent) damage heals faster than in most other creatures.

Human beings once hunted their food simply by following it without rest or food until the prey was so tired it just couldn't flee anymore.

An animal with horrifyingly toxic saliva is the komodo dragon because of all the **** it eats, human saliva is almost as toxic and for pretty much the same reason.

Humans took one of the few predators that were dangerous to them, wolves, and forced it under its control to assist in hunting, or just to keep around to look nice/be friends with. The other predators we lock in cages so we can point and laugh at them.

Human beings allow themselves to consume so much food that they become incapable of movement, or so little that they become little more than a skeleton, and in both cases it is possible for human to recover.

Human beings are capable of unimaginable cruelty/perversion directed against one another and the creatures around them, while the other creatures of its world don't even really think about committing such acts.

that last one isnt really a "fack yeah!" though is it :/

We kill and destroy other groups of humans over gods we ourselves may or may not have come up with.
We also destroy whole cultures over small slights, like the stealing of a 4 legged creature weighing hundreds of pounds that we used as a primitive transportation.
We use the bodies of large creatures that were killing machines to power vehicles that go faster then the speed of sound

We also destroy whole cultures over small slights, like the stealing of a 4 legged creature weighing hundreds of pounds that we used as a primitive transportation.

very small.