The fail to live up to their promises.
A company like Amazon is only as good as the services they provide. Sadly Amazon charge for a Prime delivery Service but simply cannot live up to the promises they make when they take your money. Twice in as many months goods I ordered on the Prime account were not delivered on time. I don't expect miracles but I do expect to get next day delivery on goods marked prime next day when I pay so much per year for prime membership. Having been let down and highly inconvenienced by Amazons failure to deliver, I cannot be anything other than disappointed with them.