This article is from the Living Barefoot FAQ, by Paul J. Lucas with numerous contributions by others.
No, but some people do not walk properly to begin with. You should
walk by placing most of your weight on the balls of your feet (the
pads in the front behind your toes) rather than your heels.
Heels are rigid and many people "slam" them into the ground,
"shocking" the legs and knees. Instead, while you should still make
your heels touch the ground first, you should shift most of your
weight forward onto the balls of your feet. The balls are flexible and
will "mold" to the contour of the surface; they also have a wider
surface area to better distribute your body's weight. Once you get
used to walking this way, it will become natural for you.
Aside on foot anatomy: The above shows off one of the most beautiful
and functional aspects of the human foot: the arch. Just like the arch
of a bridge, the arches of your feet "carry" your weight across from
your heels to the balls of your feet where it can better be
distributed. Structurally speaking, an arch is extremely strong.
As for walking barefoot, you should _always_ step down and never slide
or shuffle your feet. If perchance you do step on something
uncomfortable or sharp, you will notice before you place your full
weight down. Sliding your feet puts them as risk of being gashed,
getting splinters if walking on wood, etc. You ought to slide or
shuffle your feet only when you _know_ the surface you're dealing
with. Carpeting or tile floors do feel nice.
There is one technique that contradicts the above advice. When walking
through prickly, dried grasses, you can put your feet down, but,
within the last couple of inches, sweep them sideways in a
semicircular fashion. This will knock over the grass and you'll step
on the sides rather than the pointy ends. Take extra care when you
can't see the ground surface.
In time, you will develop a "sixth sense" about placing your feet
since your soles are a wonderful sensory organ.