I wish I could make awesome costumes.
One of my biggest wishes is to be able to go to comic book conventions and other nerdy galas and wow people with my costume. The best costumes are handmade, tailored to fit an individual, not a jumpsuit you buy online that's "one size fits all." Not only does a handmade costume look better, but it shows dedication to your fandom of choice. It shows that you put time and money into looking like a character, becoming a character, and now you get to be looked upon by jealous eyes and get thousands of pictures taken with you and possibly win some money for having a damn good costume.
Plus you could get together with friends and be badass like these guys.
In this case, handmade > mass-produced, hands down. But since costumes are a luxury and not a necessity, my issue with being picky about whether something is handmade doesn't apply.