Well, Bugsy the Celcius scale actually makes sense. Water is by far the most important thing we have on this planet. It is important in starting and sustaining life and it covers 2/3rd of the planet's surface.

So picking water actually makes sense. Celcius wisely used pure water to get rid of any random factors and simple measured the temperature of melting ice and boiling water. Again this makes sense. Boiling is to transform water from liquid state to gaseous state. And melting is to transform water from solid to liquid state. 

In practical life it makes sense too. When the temperature is below zero it s snowing above and it is raining. The Kelvin scale is based of the Celcius scale, but then they took the absolute zero temperature. So for scientific things this make sense also, while in day to day Celsius scale makes sense. In many scientific calculations that work with temperature differences you can use both Celsius and Kelvin scale.

And from Fahrenheit, well let Wiki speak for me

According to a journal article Fahrenheit wrote in 1724,[3] he based his scale on three reference points of temperature. The zero point is determined by placing the thermometer in brine: he used a mixture of ice, water, and ammonium chloride, a salt. This is a frigorific mixture which automatically stabilizes its temperature at 0 °F. A mixture of water and ice stabilizes at 32 F. But Fahrenheit did not use this point in defining his temperature scale. The third point, 96 degrees, was the level of the liquid in the thermometer when held in the mouth or under the armpit of his wife. Fahrenheit noted that, using this scale, mercury boils at around 600 degrees.

How Random can you get?

Sure there are some random things in the Celsius scale, but still so much better than the Fahrenheit scale which is designed in idiocy.