Do you ever received somebody's mail by mistake? Mistakenly received somebody's else mail?

Yeah sometimes, if it's near my street which most of the time it is I'll post it to their house but if it's far I'll just post it back in the post/mail box :3

Yes:
1. Members of my family have the same initials - many of the girls have J, and the boys have L. So when I was younger we sometimes got the mail mixed up.
2. Sometimes the person's name is similar to someone in the family and we have gotten their mail.
3. Sometimes the box #'s are transposed or next to ours and we have gotten the wrong mail.

We have always given it to the person if we know who it belongs to - or taken it to the post office employee to put in the right box.

I don't think I have ever gotten someone elses e-mail - unless you count the unwanted mail where people think I am two guys.