The Lovable Goof
The Goof lumbers through life with a smile on his face and a song in his heart. Every now and then he'll set your couch on fire or lose all your money during a weekend you had to spend in Vegas because a buddy of his there was selling him a Vespa. But he means well! And isn't the roller coaster ride of a friendship with this wildcard worth more than five thousand of your measly dollars?
Why they don't exist: You know who sets couches on fire and goes to Vegas at any point ever in real life? Sociopaths. Wildcards sure can be fun, but you'll forget all about that once their divorce storyline kicks in and they start hitting on your mom.
The Blossoming Romance Founded on an Awkward Initial Encounter
Why they don't exist: Random public encounters sound awesome, but what you're forgetting is the sheer volume of awful weirdos roaming the streets at all times. The chances of happening upon a hip, together life partner on your way to work are as slim as that weird white-haired guy who hangs out in the subway entrance, points at you and screams the date of your death every morning.
The One Who'll Make You Do Things
Why they don't exist: Remember how hard it is to do all that stuff I said before? Imagine making ANOTHER WHOLE PERSON do that stuff. In movies, gyms are places where life truths are somehow shared between buds while at the same time they're running fast and long enough to get one of those all-back sweats going. In reality, you half-heartedly pedal alone on the exercise bike and mentally craft a passive-aggressive text to the guy who rightfully canceled on you.
Why they don't exist: By the time you've matured sufficiently to even entertain the concept of your parents as real human beings, they'll have matured sufficiently that it would be laughably foolish to imagine them being even the slightest bit invested in anything other than the "Next time on Homeland" trailer. They still love you and everything, but Brody's really in the thick of it right now and you're going to have to keep your voice down until 11, OK?