We used to use Fahrenheit when I was younger so it is hardly some strange American fad, I still think in Fahrenheit in the Summer but switch to Centigrade in the winter
For the past couple of years, I've been training myself to automatically convert Celsius/Centigrade to Kelvin, just because the number is bigger, and it therefore seems warmer.
I still don't always do it. At the moment, I'm having difficulty remembering to convert Farenheit to Celsius anyhow. Americans need to stop using antiquated crappy measurement scales.