Issue is that many people have different standards and quality. Seen it all from lazy people to people that will metagame to make their character seem superior, and even people make a character sheet only to play a character with a completely different personality and agenda.

You wouldn't see it much in a 1x1, but in a group RP these traits can become infectious with people subtly adjusting their writing to counter play so that they don't get metagamed or power played out.

As for how I view 1x1s. I try to keep them the same as a group RP, but it's harder as I feel you're acting as both gm and player. Surprise moments don't always work out, and I have seen 1x1s where someone created an npc and the other player kill off that npc with their character, so communication is key in order to prevent this. :\