I was thinking earlier about, generally speaking, what makes for interesting characters. Obviously the idea of them seeming like real people is key, but to boil it down further, what makes them seem real? Is it their flaws? The great Trek characters are all pretty flawed:
Spock: Lies to himself about how logical he is, sometimes refuses to see the value in emotion
McCoy: Hot tempered
Data: Doesn't understand the emotions of others
Is being flawed/showing flaws what separates great characters like these from fun but less beloved characters like Sulu or Riker?