I go through periods where I get more or less Spam in my mailbox. Lately, it's more and it differs from earlier inundations of this crap.
When I first starting getting unwanted emails, in the late 80s, it was always perverted porn stuff it seemed. Farm girls with donkeys... did anyone really respond to that stuff? Responding was key to making it work as well, unlike today where viruses and whole programs can be activated just by opening the email. After that it was a long list of Nigerian emails and "send this to 6 friends or you'll die!" sort of stuff.
Lately, I find it's a lot more insidious. The spam I get looks like messages from real companies, trying to trick you into clicking to find out about some fake phone bill, an e-card sent by a friend, linked-in invitations, Paypal requests... they are all over the place in from where they appear to come from but the patterns are exactly the same. I imagine many people fall for these as opposed to earlier techniques but I have plenty of clues that tell me right away that they are spam.
1) it's all in English. I'm in Québec...we speak French. At the very least, official e-mails would be sent in English and French.
2) Again.. I'm in Quebec, there's no reason for me to have an account with Bank of America etc. Most of these messages claim I have an account in the USA.
3) This is common to just about all the recent ones... they send 10-50 a day, all from different people, none of which from names I know and many are quite uncommon. Imogene isn't exactly a friend's name I'm likely to forget. If you get more than one email from the same place in the same day (or within several minutes)... it's spam.
4) The logos are all wrong, and the design of the emails. Maybe because I'm a designer I notice these things more.
5) None of the companies they claim to represent send these sort of emails. The E-card one is the trickiest to spot because if the name is familiar, it is the sort of thing you might get for real.
In short, it's annoying. More so because I think many people who don't pay attention or who don't bother to learn how to use their email properly and safely are going to get ripped off or have their identities stolen or worse. I would never open an email that says "I love you" from a stranger.. and it's not just because I'm bitter!