Whenever I think I'm making an arbitrary decision that isn't necessarily the obvious best one, I try to explicitly point that out to my coworkers. "I really like this idea over the others, but I am definitely biased for x, y, z reasons. Since I'll likely be the one doing the work, I'd obviously prefer to do it that way. Is that foolish in this case, or would folk generally be okay with it? I'd love it if somebody tried to change my mind."

Half the time I end up getting mind changed, and the final result, while still arbitrary, is better than any of the original plans would have been.