its all about the fit.
you and your cousin are wearing exact same jacket but it looks better on you because you have a slightly larger frame.
Imagine how much better your overall look would be it you got jacket tailored.
Tailoring doesn’t have to mean skin tight, you can still have a loose fit (think old school 1940′s). But shoulders & sides should fit.
I don’t know……whats the point of color coordinating your tie & jacket, shades & nice colored pants just to have a baggy sports coat that adds weight to frame and makes it look like you have a gut???