I don't know about other countries, but here in Australia post offices are open Monday-Friday, 9-5 (with the exception of some smaller ones being open until noon on a Saturday) and there are massive queues around lunchtime.

And that's assuming there is a post office near you (or you have a car), and you're able-bodied enough to get there independently.

I can say from personal experience that I have point blank refused to pick up Signature on Delivery (ie, the sender instructed the postal service not to leave the package on the porch) items from the post office in the past and demanded a refund from the seller. I'd do the same if I was asked to go down there to verify an account for Uber or whatever.