Maybe arbitrary isn't the right word, because not all rules are made on a whim, some actually have a valid reason behind them. I suppose I determine if it's arbitrary if I either know the reason the rule was created, or I can't think of a good reason why it was, or I can deduce why the rule was made. And of course the consequences or context of the situation changes whether I follow the rule or not. Not that I think I should follow the rule, but I have to take into consideration what I want out of life and what the risks vs rewards for breaking the rule are, and am I willing to take that risk. For example speeding, the reward is I get to my destination faster, which if I'm late for a potentially lucrative meeting and the speeding gets me there on time, then I would factor that into my decision to speed or not. Not that I think speeding is necessarily wrong, it's just a rule with the consequences of being pulled over (which would make me really late) and being fined, which would cost me resources.

How do you determine which rules might be arbitrary, and does your decision to follow them change based on potential consequences or the context of the situation?