your joints will thank you

One of my pet peeves:
Find a line on the ground
Make sure there is a clear path
Walk normally, with the line between your feet
Look down as you're walking
Are your feet parallel with each other, and parallel with the line?
Or are they angled out at 33 degrees or more?
If they are not parallel, you are not walking correctly and you are putting unnecessary pressure and stress on your feet, ankles, knees, hips, and legs.
When you walk, your feet should be parallel.
Your joints will thank you.

Part 2
Are you a runner?
Running is VERY hard on all the joints below your waist... and even harder if you're doing it wrong.
Have a running partner watch your gait from the side and from behind to see if you're stepping wrong or if your feet are doing weird things.
You should be landing mid-foot and rolling forward, not striking heel first, and from the back you should be in parallel the whole time - no landing on the inside or outside of the foot.

Personally, I don't recommend running as an exercise at all, but people are so enamored of it, I can't really stem the tide. Use sparingly.