That's a keen observation, skip
If you've selected the right rod/line combination for the fly and conditions, the cast is pretty easy all day, whether wading deep or shallow, and it also makes it easy to compensate for wind, etc.
Part of being a good fisher/caster is selecting the outfit and being consistent. Some enjoy the challenge of fishing experimental line/rod/terminal gear on occasion, but for serious fishing the better casters will use their tried and true, perfectly balanced outfit so they can concentrate on swimming the fly instead of trying to get a good cast out.
Your friend had the right gear and a fluid casting cycle, and can probably fish the whole day without breaking that consistency.
