Yes, especially after an already long, hard ride. I did a local ride last week called JAWS. The route I did was 58 miles and had 5,000 plus feet of climbing. Many of the grades on the route were in excess of 15%. I had to walk the last third of one of them and was relieved to find out that another rider I know--who races competively--did the same. Of course, he did the century route and got to the hill with a number of extra miles under his legs, but still. The point is that it's tough stuff and sometimes your legs, lungs or both just don't have it in them. I do the best I can, so I try not to beat myself up when I have to get off and walk. Whatever gets me home safely.
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher