Being Human Sucks

I don't want to be human! I want to see gamma rays! I want to hear X-rays! And I want to - I want to smell dark matter! Do you see the absurdity of what I am? I can't even express these things properly because I have to - I have to conceptualize complex ideas in this stupid limiting spoken language! But I know I want to reach out with something other than these prehensile paws! And feel the wind of a supernova flowing over me! I'm a machine! And I can know much more! I can experience so much more. But I'm trapped in this absurd body!

—Cavil

Some times writers portrait various forms of Transhumanism, cyborgs, vampires/werewolf and other transformations as bad thing. This trope is completely opposite. It comes in the following forms:

Person undergo traumatic transformation into something non-human: Vampire, werewolf, cyborg (In a setting where it is not normal), Energy Being, but instead of angsting he celebrates because he didn't like his former life anyway;
Vampire, Werewolf, any other non-human transforms into human and angsting about how lame his new form is;
Human dreams of becoming non-human because his life sucks. How close he will come to actual transformation depends on the setting.

Good friend of Puny Earthlings: Puny Earthlings is more about how other species as a whole see us, this is the view from individuals who are human (or have been). It's a setting trope, this is a character one. Being Human Sucks may be brought on by an individual realisng they are/were a Puny Earthling. See also Humans Are Flawed.

Often the reason behind Transhuman Treachery. See also Cursed with Awesome, Puny Earthlings. Contrast Tragic Monster, What Have I Become?, Karmic Transformation and Face Monster Turn.

Examples of Being Human Sucks include:

Comic Books

Transmetropolitan has Foglets, who are nanite clouds that were human and went a process to become nanites, usually for this reason.
- There are also the Transients. Genetic engineering has allowed people to alter their bodies in many ways, but being an animal isn't all it's cracked up to be. Being an alien, however, has a certain appeal.

Fan Works

Type 3 is Eve's reason for becoming a Succubus in The Return, she is more than happy with her new species and all the perks it comes with. Actually most Succubi seem happier with their new species after conversion no matter how (un)willingly they went through it...don't stop to think about that though.

Film

Avatar: Jake Sully was more than happy to completely abandon his crippled human body and permanently transfer his mind into his Avatar body.
Fright Night. "Evil Ed" is bitten and changed into a vampire. He apparently loves it, enthusiastically hunting down and attacking Peter Vincent.

Literature

Bella from Twilight certainly feels this way.
In Terry Pratchet's Discworld stories, the Librarian of Unseen University is an orangutan who used to be a human wizard. He's very happy with the practical advantages of his current form, like the ability to climb shelves without a ladder or the ability to intimidate people into returning borrowed books on time and undamaged.

Live-Action TV

Brother Cavil from Battlestar Galactica provides us with page quote, as well as embodies this trope to a T. Interestingly, he himself is not a human, but a Cylon in the shape of a human. The page quote is all about how he hates his human body and how he wants to become a full on machine. His mother's response is that she's disappointed he never tried to follow up on his "perfect machine" idea, instead taking out his frustration with his form and his limitations on Humanity (and other humanoid Cylons).
On Buffy the Vampire Slayer when Anya changes from a demon into a human she complains about a number of abilities she lost in the switch. Probably her biggest concern is the simple fact that she is now doomed to die, whereas a demon can live forever so long as it doesn't get killed.
True Blood - one girl was more then happy to find out she's a vampire now telling how her human life sucked.
In 'The End':

Castiel: I'm human.
Dean: Well, welcome to the club.
Castiel: Thank you. Except I used to belong to a much better club.

In the Star Trek the Next Generation episode Deja Q, god like alien Q is turned into a human and does virtually nothing but bitch about it.

Tabletop RPG

Call of Cthulhu (tabletop game) supplement Cthulhu Companion, adventure "Paper Chase". A book lover named Douglas Kimball meets some ghouls, goes to live with them and eventually becomes one himself. He keeps his original personality (except for starting to eat human bodies) and he loves his new life. He doesn't need money, have to dress for dinner or meet people (living ones, anyway). He can spend all of his time reading.

Web Comics

Lord Selnikov takes surprisingly little time to reach this conclusion in Girl Genius. After having his War Stomper blown up under him, he finds himself 'resurrected' as a head in a bottle. Dr. Sun assures him that they'll build a new body for him if he'll answer some questions, and he seems to like the idea, commenting that "My original was no great shakes, after all." He was upset about being Legally Dead, but when he realizes it means that he's automatically divorced from his wife, he perks up even more. "Can I get a brass plate that says 'Reanimated Abomination of Science' bolted to my forehead?"
Nick Zerhakker from Skin Horse eventually comes to this conclusion when he sees a Hot Scientist change clothes inside him: When human, he was a pathetic no-life who had never seen a girl up close.
- Not to mention the satellite connection. And the weapons. And the fact that he can fly.

Real Life

British neurologist Oliver Sacks reports in The Man Who Mistook His Wife For a Hat: A man suffered brain damage from drug use and, as a collateral effect, gained a dog-like sense of smell for a few weeks. After the effects wore out, he says the world felt gray and flat and devoid of beauty.