[quote=SilverRain]
Another take on why "everything else is ignored" is because there literally isn't enough players. A 1x1 RP has only two people - perfect for a romance story. If you check the non-romance 1x1s (such as fandoms or historical retellings) they sometimes come with the requirement that players need to take on more than one role. I for one, am able to take on multiple roles, but many RPers can't (or at least don't want to).
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It's not a necessity to make a two-person story a romance. I could see it as convenient or easy to think up, but not necessary.
E.g. Two people (strangers/family/acquaintances) stuck on their own after some crisis, or both lost in the same place, trying to figure out how to survive/get out of said crisis.
Or a two-man mission of whatever kind.