I'm not a hardcore cyclist - covering 60 miles on a loaded bike in a day is about my limit. But something I mulled about while cycling on Mull (ha ha) is why distance isn't always related to pain. One day I covered a modest 25 miles - and 5 miles from my destination I hit a bit of a wall and struggled for the next couple of miles. The next day I did 45 miles over terrain which was, if anything, slightly tougher, and again 5 miles out I had a bit of a wobble. So on day 2 I only felt the strain when I had covered twice as much ground as where I felt it on the first day.
The answer is obviously psychological. Day 1 I expected to be easy - a quick couple of hours dawdling along before I got some lunch in and set up tent, and was disappointed when my legs started to say "this ain't easy" before I got there. Day 2 I expected to be hard, so I prepared myself for a full day's effort, set my sights high, and sailed past the 20 mile mark with ease. By the time it started to hurt at 40 miles, I could tell myself "you've come so far already, you've done well, just these last few miles to go."
This is why I emphasise to my clients that they must stretch themselves with sustainability targets. I've seen many people set apparently easy targets and struggle to meet them - mainly because they expect success to be almost effortless (so they fail to make the effort required). If you set tough targets, you will struggle the same amount, but achieve so much more. The ambitious approach puts you and the organisation in the right frame of mind to do things properly - to make the changes you know you need to make, to budget appropriately, to target problems at source rather than at end of pipe (or, better still, turn them into opportunities).
So are you going to stretch yourself or just dawdle along?