Well, not everyone and not all the time, but sometimes, you just KNOW other people are not being entirely honest. Like, they can't help it. It's a very English thing to do - you couldn't possibly say what you really mean. It would disrupt the entire stiff upper lip thing that's going on.
What people really mean when they say:
"You look like a lobster."
"Honestly I don't mind."
"I do a bit. But I've said I'll do it now so I can't really back out."
"You look fine."
"That outfit's not really that great but I want to go out and get pissed."
"I'm only apologising so you'll apologise too."
"Are you sure?"
"This is a completely meaningless statement."
"It was great to see you."
"I can't remember if I've met you before. This is suitably non-committal."
"Come if you want to."
"I don't want you to come but I'm too passive aggressive to say that."
"You look interesting/different."
"What the hell have you done to yourself?!"
"I was too busy."
"I forgot but want to sound important and have an excuse so I don't sound flaky."
"I'm not sorry at all. I want to say something insulting." (the same goes f0r: 'I'm not being funny, but...' and 'no offence, but...')
"Would you like to [insert shit task that no-one would ever LIKE to do]?"
"You haven't really got a choice. I'm TELLING you."
"I'm too tired."
"I can't be arsed."
"Am I the only person who thinks that..."
"I'm definitely not but want to seem original. And I want to be a stand-up comic so I'm working on observational humour. HAHAHAHAHA."
"I don't really use Facebook."
"I don't want you to add me, you creep/pervert."
"As I said before..."
"As you've clearly ignored what I said before I'll say it again..."
And finally, a classic:
"You look well.""You've put on weight."