I don't mean being stern-faced and only ever discussing really deep topics on your walks, but doing walks of sizeable distance or difficulty, the sort of walks that make your colleagues and family pale at the thought ...
Dunno really, not sure if I count myself as serious. Biggest (toughest) walk I have done-twice-is High Cup Nick, inc. scrambling down the nick, as a circuit from Appleby station, about 11 miles.
