...Those are the two words I hate hearing more than just about anything else. Actually, I guess I would rather hear a "you should" statement than hear "you have head lice," but those statements both evoke very negative feelings. I would be more panicked about the head lice and would be considering the extensive cleaning-of-the-house I'd have to do and I would be contemplating burning everything my head has ever touched, including my hair. I guess "you should..." is more annoying than alarming. When I hear that statement I assume that the person that said it thinks I'm an idiot. Someone telling me I have head lice would be doing me a favor (if it was true. It would NOT be a funny joke, FYI.)
Some people can be forgiven for the "you should" statement. My grandma is constantly telling me what I should and shouldn't do but she's in her nineties and has been around the block, so I will actually either listen to her, or ignore her (mostly ignore). When my parent's "you should" me, I choose to think of it as being funny as opposed to incredibly annoying because they still think I'm 14 and their "you should" statements are usually so stupidly obvious. "Are you going to cut that watermelon? You should use a knife." or "Are you going outside? You should bring a jacket."
The only time I appreciate a good "you should" is when it comes to books I should read, although I've been pointed to a few real stinkers, so I'm inclined not to listen anymore. "You should read Left Behind! It changed my life!" (Nobody should read Left Behind.)
What really annoys me is when people who have no kids tell me things I should be doing with my kids. Or people telling me obvious things, like I should get in shape, or visit every continent, or recycle, or floss, or take a shower. No duh. Do I look like I need to be bossed? I don't. And I'm just obstinate enough to do the opposite of what was suggested which is counterproductive for everyone because the "you should" suggestions are usually pretty good. I wanted to quit drinking diet Coke a few years ago and then someone said, "You should stop drinking that. Even the diet stuff rots your teeth." I thought, oh GREAT! Now I have to drink this for the rest of my life and I can't even go to the dentist because somebody told me I should do that too!
So when I hear someone say "You should..." to me (unless it's a dare. I love a good dare. Or if it's something sensible like "you should let a doctor cut that off instead of doing it yourself."); the first time is an alarm and I'm really listening, and if I hear another, it's over, my bossy non-friend who thinks I need the direction only you can give.