Fails to Climb, I don't think I ever work that hard on a ride, although I do some very long rides or rides with extensive climbing (4000-6000 feet).

That said, I really agree with the comment about making sure you've got something in the tank before you go out on the late afternoon/evening ride. Last week I was riding home from work (just 11 miles) around 6 pm. Lunch at my school is at 11 am, and I don't think I had a snack in between and I didn't have anything with me to eat. I very nearly bonked on the way home. My route is out on the edge of the desert and along a bike path, and it has no services between about mile 5 and mile 9. I thought I could make it home but about mile 6 I felt horrible. I barely made it to the first convenience store. And that was just on a casual ride. (And like you I usually eat more than enough....)