Most people learn early in life that luck and odds play an important role in their lives. Some of those people are better at playing those odds than a lot of their brethren. There are examples and metaphors galore, some of which may surprise you.
You probably weren't very old the first time you learned that the the odds on a coin toss, whether it had been preceded by a string of either heads or tails, are always the same - 50/50.
Similarly, a woman who already has three baby boys effectively has the same 50/50 shot at a girl on the fourth try as on the first.
There are examples at race tracks where betting on outcomes indicates varying odds based on people's opinions and prior race results. Still, as was seen recently at the Belmont Stakes shot at a Triple Crown for California Chrome, what seemed to be a sure thing, turned out not to be. The odds of a great horse winning those three races in a row were something less than 50/50. Something similar happens in sail boat racing in identical boats. In such cases the skill of the crews, skippers and navigators, plus the fickleness of winds, make the difference. Still, most racers begin a race among a dozen boats believing they have a 50/50 shot at winning.
Then there are residual practices in certain situations that the 50/50 assumption has to be set aside in favor of one beneficiary or another. For example, there is hardly a married (or unmarried) couple of opposite sexes that has not tangled over the right way to leave a toilet seat after use. Either way, one or the other, the user has to be continuously alert to the possibility of making a mistake in how the seat is left. Most men apparently ultimately submit to female demand that the seat should always be left down, despite a compelling case that it really is, or should be, a pure 50/50 proposition.
There are many customs from the distant past under the heading of "noblesse oblige" in which women, for example, always precede men through a door. But, in today's new world of full equality between and among the sexes in virtually all respects, has it not come to the point that the 50/50 rule should take on a broader, wider and balanced meaning and application?
Either that, or movable toilet seats should become thing of the past. Perhaps it is time for toilet makers to design toilets without movable seats. Pure habit has created stasis.
That, at least, would rid modern society of one really unnecessary irritant.