The first thing I did to clean the planet up was to take a shower before going shopping. I even did behind my ears. Then I took the shopping cart and tightened up the wheels and gave it a cleaning too. After that, I did not swear at a single person that was ahead of me on line. Nor did I curse at the idiot behind me who kept bumping me with her cart just because she wanted to give her ugly kid a ride.
In mathematics, you don't understand things. You just get used to them.