Compare: The curtain goes up. Two middle-aged men in dark suits stand next to each other. Or… The curtain goes up. An ancient woman in a robe and a six-year-old boy stand next to each other.
Which engages your curiosity more? Probably the second. In general, differences and contrasts intrigue us. They promise more in terms of variety and conflict.
Consider: The curtain goes up. One character wears grubbies and a baseball cap. He chews a cigar as he builds a sandwich that spills over a plate. The other is dressed impeccably with a perfect haircut. He dons an apron and tends a Cornish hen in the oven.
You know the audience would already be interested. And you probably recognize this Odd Couple (sort of). Both middle-aged men, Oscar and Felix approach life from opposite perspectives. Which is why it was so much fun when Neil Simon bound them together.
When you create character relationships, especially those where the characters can’t simply move on and find someone less “weird,” you set up situations where conflict arises. It may be that accommodations will be made. Or one character might kill the other one to resolve the situation.
Note: It’s important to bind the character together in a way that the audience accepts. Danny Simon said The Phil Silvers Show worked because the characters could not escape the army, and it lasted for almost 200 shows. The New Phil Silvers Show put the characters to work together in a business, which any of them could escape. It lasted ten episodes.
The first examples demonstrates physical differences. The second, differences in interests and perspectives on life. Contrasts can also come from differences in power, wealth, values, morals, and skills. Flaws and virtues can also create engaging juxtapositions. In fact, powerful stories can be created by comparing these as world views (greedy Potter and generous George Bailey in It’s a Wonderful Life).
Dramatic opportunities are endless. The writer can have a character moderate a flaw (or a virtue) by taking on approaches of the contrasting character. Both characters might move toward each other. In An Officer and a Gentleman, secondary characters, one too generous and the other too selfish, flame out and that helps the main characters find middle paths. Or, one character can kill (or defeat) the other.
If there is no contrast, dramatic possibilities are limited. If there is a big contrast, more possibilities arise. Good romances have always demonstrated this, with the guy and the gal separated by an important difference and held together by some plot device. For larger groups, types are often used. I haven’t researched it, but I think Hollywood figured out how to do this with war movies where each soldier in the troop had easily recognized traits. Cowboy movies (The Magnificent Seven, Silverado) created similar teams.
Probably the most recognizable and obviously diverse group in a shared relationship is Star Trek’s crew members. A still photo is enough to see their differences. But the variety of perspectives and concerns, once they move into a story, is impossible to miss. Note that they are all trapped together on a five-year mission, often confined to the bridge of the Enterprise.
This is not to say that such stark differences are necessary to creating a good story. Think of The Dead Poets Society. Seven of the characters (the ones who comprise the Society) are male, intelligent, students at the same school, white, about the same age, and (eventually) absorbed by poetry. The even dress the same.
It had to have been a challenge to differentiate these characters early on and to find ways to highlight how they helped each other come of age. (Something similar is done with female students in the film, The Prime of Miss Jean Brodie.) But the writer (who won the Oscar for is work) did it. The contrasts are there, and put to use for drama, but the subtle exposure of the differences is done with power and grace. It’s worth exploring.