Take this sign at my local ASDA grocery store. Is it right?
Well, no it's not. But it's not the only supermarket that's been having less/fewer issues.
A couple of years back Tesco changed the wording on their fast-track checkouts to avoid any - as they called it - linguistic disputes. They replaced the '10 items or less' signs with...
People often use I because they want to come across as being polite. Or a bit posh. Wrong! So when do you use me, myself or I?
The absolutely easiest way to remember is to simply take the other person out of the sentence.
Jack and I/me went to the cinema.
I went to the cinema.
The letter had to be signed by Sharon and I/me.