perplexities

Lately I've been prepping my students for the big state standardized test (more thoughts on that monstrosity later), which means daily I am spewing out things like "What is 3/5 + 7/10?" and "What tool do you use to measure force?" (the answers to which are 1 3/10 and a spring scale, respectively, in case you were curious).  All of this rapid-fire review has given rise to some questions of my own that have been plaguing me for some time and to which I have not yet found satisfactory answers.  Perhaps you can help...

Why are doors to doctor's offices always so heavy?  Aren't people generally there because they feel unwell?  And when you are ill isn't pushing heavy objects pretty much the last thing you want to do?

Why is it acceptable for my dog to lick me and I think it's adorable "kisses", but if another human were to lick me I would be a little freaked out?  And perhaps not want to be around that person quite so much...?

Why does every green thing on the planet grow in my backyard, but very little grass?  And can you really call clover/violets/dandelions/weird green leafy mystery bushes a lawn?

Why do birds try to run from things?  Don't they remember they have wings...and that whatever is chasing them can't fly?

Why does the local carwash have a "best wash" but also offer a step up called an "extreme wash"?  Isn't the whole meaning of the word "best" that there isn't anything better?

Why do men love ugly chairs so much, even when compared to equally comfortable stylish options?  Why do they always gravitate toward nail-studded leather or marshmallow-puffed recliners?

Why do we have eyebrows?  And if they serve no function why didn't we decide years ago to just start shaving them off completely?

Let me know if you have any reasonable explanations to the above perplexities, and if perhaps you have some of your own.  I may be able to help, but only if it's a topic on the fifth grade test.