Ironically one of my motivations with exercise is to avoid being tired or fatigued. I notice a big increase in energy levels when I'm getting regular exercise.

Ironically one of my motivations with exercise is to avoid being tired or fatigued. I notice a big increase in energy levels when I'm getting regular exercise. Better to be a little fatigued at the end of an exercise than be fatigued for the rest of the day. I also agree that exercise should never be painful. Unfortunately, we have a "no pain, no gain" mentality about exercise in this country. I don't even think the exercises advertised as "extreme" (ala P90X/Insanity/Crossfit) need to be painful, but some people will push themselves more than they should (Crossfit in particular is notorious for poor trainers overpushing people to injury).