My e-mail that I used to sign into a bunch of websites years ago tends to get some curious messages sometimes. Mostly because I used that e-mail to sign up to everything under the sun years back.
I've gotten more selective these days. Live and learn kids.
That being said, there are times where I get an e-mail from an unknown person, with an attachment from someone. That e-mail automatically gets flagged for deletion. Too much of a risk that something is going to happen.
People are sneaky, some of them attach these on promises of health and wealth. But never open an e-mail from someone you don't know personally. And even then with attachments precede with care. It's possible they could have gotten hijacked as well.