I hate over-exerting like that. A lot of people think it's a good way to get in shape - that you can do nothing all week, and then just way overdo it on the weekend, but I know damn well that doesn't work. It's far far better to "grease the groove", doing lots of shorter workouts where you never quite go to failure. Think about how animals in the wild play or hunt. A cheetah will chase its prey, but when it becomes clear that it's using too much energy, he just stops, in case he has to try another chase, or has to flee danger - they never go all the way to failure. Anyway, the hardest thing is when you're trying a new ride and you don't know quite what it's like. Sure you can read about the route, look at the elevation map, but you never know exactly what it's like until you actually ride it. What's harder is with a loop route you can't bail out once you pass the halfway point, the shortest path is just to finish the loop.
I know there's nothing else more boring that other people's health problems (except for maybe other people's dreams). I just wish I could feel a workout in my legs, instead of getting in my lungs, or just my general aerobic system, or my back and my spine and my neck and my bad shoulder and all that garbage. I really miss being young, in every way, mentally and physically. Those who say they're happier as they get older are suffering from two problems. First is the killing of their brain due to alcohol, TV, and just general lack of stimulation, as they become more retarded they become happier. Second and primary is self delusion; it's the same mental power that let people think the horribly stupid expensive purchase they made was wise, or that there is a god, or that immigrants are to blame for their woes - it's a powerful semi-concsiously created delusion which allows them to believe some ridiculous fiction which lets them get through life. As you get older the delusion that you're happy with yourself can be gradually built up over time until you forget it's a delusion and you're just pretending all the time.