Open Mouth, Insert Foot - Conversational Dead-Ends

We've all done it, said something we regret. Something that brings the conversation to a screeching halt, followed by awkward silence and the sound of crickets chirping. It's a conversational dead-end.
I frequently find myself saying the wrong thing.  My very wise father-in-law once said, "don't open your mouth unless you're changing feet."  While I can't offer a cure for foot-in-mouth disease, there are a few common phrases that are almost never a good idea.

1. Lighten up - It may seem like a good idea to say this when you're friend is getting all hot and bothered about something.  They're raging and you want to calm them down.  You say, "lighten up, buddy, it's okay."  But think about it, does this ever work?  Do they ever just calm down and get over it?  No.  Instead they now direct some of their anger at you.  Here's why.  They are upset - whatever they're griping about is important to them.  You have essentially said, "your problem is not important, you're just making a big deal out of nothing." That's never a message people take kindly to.  A better response - get on board.  Agree with them.  Say, "You're right, I can't believe those jerks, how can they be so stupid, I HATE them and I hope they DIE."  (okay, maybe that's going a little bit too far but you get the idea)
2. Welcome to my world - think about the times you've had this said to you and how it made you feel.  Did you feel welcome?  Didn't think so.  Typically, this comes after a complaint has been lodged.  Your friend airs her/his grievances and you say, "welcome to my world."  Basically, this translates as, "you think you've got it bad, hah! I deal with that kind of crap all the time."   It's never a welcome phrase.  What your friend really wants is commiseration and empathy.  You still get to join in the complaining but drop the one-upmanship. Say, "Oh I know, that really sucks, I hate it when that happens."
3. It is what it is - who's the genius that came up with this one?  We know it wasn't Bill Clinton.  People say this all the time in reference to their friend's or even their own complaints.  I may be alone in this opinion (a common occurrence). This phrase usually comes after someone discusses a bad situation.  For example, "the boss is making us work on Saturday this week, I hate working on Saturday, it's not fair!"  Then the friend/co-worker/stranger on the street will shrug their shoulders, throw up their hands in defeat and say, "It is what it is."  Brilliant!  This means, "yeah, it sucks but there's nothing you can do about it so just accept it."  For some reason, this always grates on my nerves.  I want to say, "NO - it's not okay - I'm mad as hell, and I'm not gonna take it anymore!"  But maybe that's just me. 

So, let's hear it.  What are some phrases that get on your nerves?