Yu want to wear shirts that make you look longer if you want to appear taller and leaner. If you want to appear larger in the shoulders and arms, you wear horizontal shorts. It they are too long or too bold, they will make you look shorter.
I never really thought of stripes on a shirt but this makes sense. I always hear women saying to avoid long lines if you are curvy and use them if you are too skinny.
I was always told, as a female, to avoid the horizontal lines because they make you look fatter. I never had vertical line shirts though either. I just avoided stripes all together unless they were pin stripes
I don't care for stripes in general so I very seldom wear them but I can see the difference for sure. It is amazing how the eyes trick the mind. Goes to show we can't always believe what we see.