I think I was in my teens before I copped this one - I knew it was et cetera, but I thought the "t" in the abbreviation was the t in cetera, not et.
As ever, these threads are full of criticisms of regional usage and dialect that most people wouldn't use in formal writing, but do on MN and FB because they're conversational.
Btw - the less vs fewer rule apparently comes from one person who decided that's the way it should be. There are loads of exceptions, mainly around money, volume, distance etc (one item is 10 pounds/litres/miles less than another, not fewer).