Who's the Dumbass at Canada Post?

I have never had a problem with Canada Post before, until yesterday. Mind you, this isn't a big issue, just an odd little mess up:

I mailed out the wedding invitations on Monday (no turning back now); when I came home from work yesterday and checked the mail I noticed one of the invites had been returned. My first thought: we had the wrong address or accidently typed the wrong address. But, there was no return to sender sticker on it. No, some genius at Canada Post mailed the invite to the return address not the mailing address. The distinction between mailing address and return address seemed fairly obvious, at least to me... The mailing address was on the front of the envelope with the stamp placed in the upper left-hand corner; the return address was on the envelope flap (doubling as a extra way to keep the envelope closed). But somehow, it was sent to us... go figure.

By the sounds of things, however, the other invites have, so far, made their way to their correct destinations. Hopefully this was a one time, weird occurance.

And that is my Canada Post Rant...