I think most of us agree wind trumps everything else in winter misery. If it's 25ºF and perfectly still, it's great outdoor weather. If it's 35ºF and the wind is blowing at 30 mph, you go inside and drink.
A couple of inches of ice all over every surface.
An eighth of an inch is enough to bring chaos.
In most of the country, a quarter inch of ice is the criteria for an ice storm warning and is enough to shut down a city.
Places that don't get freezing rain much, it's even worse - especially if those places get enough regular snow that people think they know what they're doing. As an example, I remember one storm we had in Salt Lake really well - the storm came in a little warmer than forecast at higher levels, so instead of the initially forecast 1-2 inches of snow, we got 0.09" of ice. The airport shut down, there were something like 500 recorded car accidents...I don't think the airport would shut down completely for even 9 inches of snow.