This question originally appeared on Quora, the best answer to any question. Ask a question, get a great answer. Learn from experts and access insider knowledge. You can follow Quora on Twitter, Facebook, and Google Plus.
Answer by Kah Seng Tay, an identical twin:
I'm an identical twin of many years, with my other twin—ahem—within close proximity (through school, home, and work) for all but three years of that.
I have a list of these difficulties:
The comparisons, from parents, teachers, relatives, friends, etc. Just having a twin makes you a magnet for more of such thoughts, especially growing up in Asia.
The competition, mostly from myself and my twin. Growing up, going to the same school and all, it's difficult to be the "worse" twin on any dimension—studies, sports, looks, etc, especially if we're supposed to be identical twins.
The communication: People thinking they can tell me something so that my twin will know. Or the other way round, and them having the expectation that I would know magically. No, we're two different people! Communication between us isn't free and instantaneous.
The assumptions: Do you have ESP, telekinesis, the same tastes? Have you ever dated another twin? [Insert twin stereotype here.]
The dilemmas: If you're close to your twin, then you're always facing the same dilemmas of whether to do stuff together (go to the same school, pick up the same sports, join the same company, found a startup together) or instead having our own separate adventures. Eventually, it all equalizes somewhat, depending on whether you're really twins or not.
The mistaken identity, the obvious stuff: People constantly mixing up my twin and me, either by accident or because they didn't want to put in any effort . These accidents also happen over email or IM if your names are similar.
The mistaken identity—with real-life consequence. You don't ever expect this, but it has happened to me: Getting stuck outside U.S. Customs after a long 24-hour flight because "I'm already inside the borders," when I was just next in line after my twin. Same date of birth, same face, same home address, similar names, but definitely not the same fingerprints? How does their system even work? Miraculously after several hours, I wasn't deported or thought to be a terrorist. Can't remember if this happened twice, once more when my twin never left the country.
The undiscovered mistaken identity: The absolute worst and hardest part is this mistaken identity, not being discovered at all. Imagine all the people, whom only my twin knows, walking by me and wonder why I am aloof, arrogant, or forgetful, not recognizing or remembering who they were. And all my friends that my twin doesn't know, wondering the same about me without me even realizing this. As a twin who went to the same (large) schools or workplaces, people are probably wondering this about me half the time!
More questions on Quora: