Identical twin of 30+ years. The other twin within close proximity (school, home, work) for all but 3 years of that.
  1. The comparisons.
    From parents, teachers, friends, etc. Just having a twin makes you a magnet for more of such thoughts. Especially in Asia.
  2. The competition.
    Mostly from ourselves. Growing up, going to the same school and all, it sucks to be the "worse" twin on any dimension - studies, sports, looks haha. Especially if we're supposed to be identical twins.
  3. The communication.
    People thinking they can tell me something so that my twin will know. No, we're 2 different people!
  4. The assumptions.
    Do you have ESP, telekinesis, the same tastes. [Insert twin stereotype here.]
  5. The mistaken identity.
    People constantly mixing up my twin and I. Either by accident or because they didn't want to put in any effort (50% odds are great to gamble on huh). Happens even over email or IM if your names are similar.
  6. The mistaken identity - with Real Life Consequences™.
    Getting stuck outside U.S. Customs after a long 24hr flight/journey because "I'm already inside the borders", when I was just next in line after my twin. Same date of birth, same pic, same home address, similar names, BUT DEFINITELY NOT the same fingerprints? How does their system even work?
  7. The undiscovered mistaken identity.
    The absolute worst part is probably all the people, whom only my twin knows, walking by me and wondering why I was aloof, arrogant or forgetful in not recognizing or remembering who they were. Without even me realizing this! As a twin going to the same school or workplace, this is happening to me in 50% of random interactions!
  8. The dilemmas.
    If you're close to your twin, then you're always facing the dilemmas of whether to do stuff together (go to the same school, join the same company, found a startup together) or not and instead have our own separate adventures.