I think the world could use a little more honesty. I'm not saying that we should walk up, unprovoked, to someone and say something that could seem mean. For example, walking up to the ill-dressed woman in the Target and say "You know, those sweatpants don't go with your silk top." You could tell a random stranger you love her hair or something, and that would probably make her day.
We should be honest when it's asked for, especially with our friends and family. I personally would like to know when I've done something annoying or ticked somebody off. Chances are that I've done it unitentionally and would like to make amends. In turn, I could do a better job of telling who has done the same to me.
But we don't. We usually bite our tongues and silently steam until we blow it out of proportion and make it a bigger deal than it ever was. Then, when the offending party asks "What's wrong?", we either say "Nothing" when we're clearly upset or, the classic, "You should know. And if you don't, I'm not telling you."
Communication really is key to making any relationship work, whether it be friends, significant others, colleagues, or family members. A simple "That was mean; I'd rather you didn't tease about that" can go a long way.
Additionally, we should mean what we say or do. Don't act like you like me if you don't. Don't say you liked my chicken if it was actually gross. Do mean it when you say I look nice.
We don't need to nag about the things someone says or does that we don't like, and there can be a delicate balance between occasional reminders and nagging. Also, we don't have to bring up every single thing. It may truly not be worth getting upset or worried about. However, the more we openly discuss our feelings and reactions to things, the fewer shouting matches that will occur.
Talk. Talk a lot. Listen even harder. I hate being told "We need to talk", and I hate having to come to a point where I need to say it. The more two people work together about their relationship, the better their relationship will be.
Now, if there's something you don't like about me or my character, I reserve the right to respectfully disagree. I may not change that behavior completely, but I might avoid doing or talking about it around you. You have the same right.
Finally, don't forget to bring up the positive too. We're all insecure enough as it is, so the more we hear about the good things, the more we'll believe it.
Of course, don't forget to say "thank you." Remember, we're all in this together.
"The race is against [the negative influences in this world], not against each other."