A few years ago we installed a 6 foot tall wooden privacy fence in our backyard and drowned it in clear sealer. Sadly, only two years later, it needed to be re-sealed.
The original sealer did a lousy job of keeping it's beautiful cedarness, so we opted to stain it this time around in addition to sealing the wood. We only had enough redwood stain to do one side of the fence, and enough red mahogany stain to do the other side.
Brunette self, "Hon, why don't we mix the two stains together?"
Blonde spouse, "Why would we do that? We might run out of color!"
Brunette self, taking deep breath, "Honey, wouldn't we run out regardless of whether or not we mixed them, since we have equal parts of both?"
Blonde spouse, "No way! I'm going to paint the outside redwood and the inside mahogany!" Result? Two toned fence.
Brunette self resorts to abandoning ill-logical debate and wonders if Blonde spouse shouldn't be running for president.