What is SPAM ?
When you receive an e-Mail from anyone [jSmith@gmail.com] assuming the Sender Name and the Real Sender […@…] marry up then it’s NOT SPAM. This is true for most of the e-Mail you will receive.
So when they don’t: it is SPAM. Sorry for the reverse explanation !
So how does this happen ?
Many people/companies [web-sites] use third party e-Mail services to send out their eMail; this could be a Goggle gMail account or frankly any service.
It is perfectly OK if the person or web-site [run by the real owner] uses a third-party e-Mail server to process eMail. Such an e-Mail could/would be considered as SPAM because the sender’s real e-Mail would be different from the purported sender [the web-site e-Mail Server]. This is GOOD SPAM ! Or it should be ?
Common sense will prevail.
Real Bogus SPAM [depending on your point of view] is when someone makes an e-Mail shot via a third-party server, i.e. they want to send a Zillion e-Mails, but not from their account. Maybe there are good reasons for this. We are not judging. If they do this, as above, your ISP and or e-Mail program may mark this as SPAM. Actually some ISPs are fussy [gMail] – others not so much depending on the tech used to send the e-Mail.
That sort of discussion is not important in the context of this POST.
So: bottom line – the e-Mail may be valid and quite bonefide, albeit that it didn’t originate or was not processed [sent] by the same address as the one stated as the e-Mail Sender Name. So, using an example the Sender Name on the e-Mail could be Richard Nixon [email: firstname.lastname@example.org] but the actual sender could be email@example.com. Looks a bit suspicious ?
If however, the e-Mail does NOT have an attachment then there should be no harm in looking at the e-Mail – just don’t open any attachments.