I've noticed a few threads where folks have gone back to driving the car or feel they can no longer cycle on city streets.
I'm kind of doing that the last 10 days or so. Visiting family in Canada, where there's a ton of snow, and I've been doing little physical exercise (except for massive amounts of shoveling)
I have to say that the lack of cardio exercise early in the morning leaves me feeling sluggish for the whole day. Even walking to the grocery store or shoveling the driveway doesn't help much.
I would have to replace the cycling with some other activity or I'd become a complete grouch for the rest of my days. [edit: I'm not planning on giving up cycling... too much fun, but I am just speculating here... since I can't get out for a bike ride.]