I'm REAL picky about who I'll pace line with to the point that I basically don't do that anymore.
I enjoy riding with groups but I've learned to be cautious about being aware of the riders around me. If there's a hot looking woman on the ride, stay away from her. It's not the hot woman that you have to be wary of so much as the goofy things men riders will do to get close to her.
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My greatest fear is all of my kids standing around my coffin and talking about "how sensible" dad was.