I am imagining everyone on my front porch with me...
and if you listen carefully you can hear one of the cats.
One thing that I didn't mention, to avoid having to sew the side seams over, the bottom of the arm hole needs to meet the edge of the piece of clothing when you cut. For me if it's an article of clothing that already fits me, it works. If it's larger the side seams would need to be resewn as well. Extending the arm hole out does not work unless you don't care if your bra shows. It is also the best reason to use a sleeveless shirt pattern for this.
This works well with skirts too. An example of how I did this can be found here. The pictures in this post also provide an example of what I mean by the side seams.
Two other things as I replayed the video:
-This dress has a dart. To make a new neckline/arm hole for this I would have to go below the dart to cut.
-I think it's really funny that my verbal tick was "so." If I were a perfectionist I'd probably have done the video over. But I am not so there you go!
P.S. I've never tried this with something that has sleeves but I have some ideas now that I want to try...