I've cycled to work over the last 2 winters -
first year I was on a slow mtb and I used to wear jeans and "normal" clothes. Soaked frozen feet. Effin freezing rest of body, numb hands. Wrong clothing/kit as I didnt know better. Didn't enjoy winter 1/10 happiness.
second year I was now on a road bike, spd's and slightly more appropriate clothes. I was fitter so journey times were less, was still wearing tracky bottoms for leg warmth. Got some really really good lights. Discovered the wonder of overshoes halfway through winter. Got to work in the floods when everyone in cars was stranded. Had to get the bus for ridiculous snow for 1 week but otherwise coped ok. Fell off on ice once. 6/10 happines
This year I've already switched to proper cycling tights. I've got a backup mtb in the shed for when it gets really bad but I know from last year I can easily cope with frost and light dustings of snow on my road bike. I've also discovered the amazing wonder of merino wool and proper layering of clothes. Predicted happiness 8 or even 9/10, I am definitely looking forward to it.