Everybody has a weakness. They're controlling, kryptonite takes away their superhuman abilities, they're deathly afraid of spiders. In some cases, strengths can be their weakness, too: their intelligence makes them unable to empathize with others, or they care for their family so much that it ultimately endangers their friends, as well.
It happens, sometimes, that you envision an amazingly strong, no-nonsense character. They have physical strength, the ability to complete any task set before them; they're unmatched in everything they do and nobody can compare. Sometimes they're witty. They're the ultimate superhero, even if they have no superhuman abilities.
But as much as we want to strive for perfection, even these guys have a weakness. It might not be obvious, but it's there, and it's what makes characters believable. And because I recently watched Catching Fire, take a few noteworthy characters from The Hunger Games as an example:
Finnick Odair had Mags. Katniss is impulsive and distrusting. Haymitch is a drunk. Peeta has Katniss. Wiress lost her sanity. Johanna was filled with hatred.
Here's a mixed bag of characters who both have weaknesses, and strengths that are weaknesses. Finnick nearly ran into the poison fog after his former mentor, which would have cost him his life; Haymitch tries to forget so much that he lives on alcohol; Wiress is super smart but her mind is so shattered that it was pure luck that somebody figured out what she was jabbering on about in relation to the Quarter Quell arena.Everybody else's 'weaknesses' are also the only reason they survived for so long, by channeling their fears and emotions into keeping them moving forward.
And guess what? Everybody loves these guys. Everybody can relate to them. Everybody thinks they can reach into the book (or, heck, even the films) and shake their hands. They're believable simply because they're not as perfect as some of them look.
Everybody has a weakness. Even my super-strong, super-fast bionic super-soldier has a weakness. Want to know something fascinating? Take a second look at the list of THG characters: only one of the weaknesses that I listed was a physical weakness (Haymitch's drinking; although, that stems from a lot of psychological issues). Everybody else has emotional or psychological weaknesses.
Take a look around you. Study your friends, your family. Odds are that whenever they founder, it's something that's not manifested in a physical thing.
I'm not saying that weaknesses can't be physical. Maybe they're sick, or they have a broken arm or a leg, or they can't run as fast as everyone else. It happens. A weakness is a weakness, though; it's something that will make your characters believable and help your readers to empathize and sympathize with them. Often a certain part of the plot arc will even focus on a character trying to overcome their weakness, and that right there is a great piece of character development.
Give your character a weakness. It makes them human.
Thoughts or Questions? Let me know what you think!