Most people, from my observation, are annoyed by the lack of consistency. I fully understand he runs a one man brand and has plenty other commitments in life other than filling out packing slips and drawing rats on polymailers. What I've seen is that he can't be consistent and relatively reliable. @purveryor relayed that his homie ordered a week ago and already got his shit yet dude is still waiting after ordering his jacket 2 months ago. I know slip ups happen and whatnot but when someone is paying $64 shipped for a piece of nylon and polyester with some plastisol on it, I too would expect at least a mild level of customer service. It comes to the point that if koopz won't even respond to emails nor hears concerns/requests/criticisms, why even have an email or an ask button on tumblr. Although I have not been in the same situation, I empathize with anybody who has a -$64 on their bank statement yet nothing to show for it.
edit: like i've been saying, i'm just a fan of the dude's work and would like to rep it out here more, it's a bummer i couldn't do so sooner