they're just people. are you suggesting they should work round the clock, without stopping (maybe not even to eat and drink! hey!) i mean, doing things take an amount of time, and doing more things takes more time.
remember, the people doing the actual handling of your order didn't get any extra money from you to do their jobs. it just went to the post office as an entity, to handle your order, and they are in fact in the process of handling it.
they don't "have" your stuff except to handle it, nor do the workers directly "have" your money. but they do have to regularly take in money so the people working there can get their regular paychecks, right?
keep in mind: you can choose the timing of your order. postal workers can't choose the timing of holidays, or choose how many packages go thru them and when, or choose to add hours to a day or to not need sleep or money to do their jobs.
well, maybe you have your stuff now.