Never really happens, honestly. When a package gets delivered, mostly to my neighbor upstairs, they make sure to ring BOTH doorbells first. I always make sure to check, but it's usually not my concern lest I KNOW I'm expecting a package.
However, what DOES tick me off is what they do if no one answers the door in time. Say, I'm out, and at the same time, my neighbors upstairs are out. They either
A) Leave it on top of the wall mailbox under the tall patio, which is placed in front of the garage door (my neighbor's car is often conveniently parked in that section, so the mail is easily hid if it's a package)
B) Leave it under said mailbox
C) The worst, leave it right next to the single stair in front of my doorstep for every one to see.
I particularly HATE C. Although it's mostly often not my mail, I get worried if it's either my upstairs or downstairs neighbors', and it's out in plain sight. Someone could fucking march up my steps and take the package without me knowing.
And half to most of the time, it's ALWAYS C.
I'd rather get that "Sorry we missed you" note than have a package out in plain sight in a semi-bad neighborhood.