"NEVER READ THEM, no matter how curious you may be."
Good advice----sort of.
I get over a hundred LEGITIMATE emails that I want every day, from three email distribution lists. And then of course I get a lot of spam.
All of this comes through Yahoo.com, and truthfully, Yahoo.Com does a pretty good job of identifying spam, and it gets shunted off to my JUNK subdirectory.
BUT! There are inevitably some unidentified, and left behind in the INBOX. Some of those I can tell immediately by the subject line or stated sender are not legitimate, and I click the icon that declares that message to be spam and shunts it to SPAM. But sometimes the subject line suggests that the message just MIGHT be an email from one of my lists. Even if I'm sort of convinced that it's likely to be spam, I don't want to declare it spam at that point, because of Yahoo's trainable email spam identifier routine; I don't want that routine to decide (on the basis of a wrongly icon-clicked message or few) that that sender (one of my lists) is a spam source. In that situation I really must, I feel, open what might be spam. If it is, I IMMEDIATELY spamify it.
Of course I never open an attachment in an email that I'm not really sure is non-spam. And of course I never click the "unsubscribe" button on a spam message.