I hear this over and over. "I just tell it like it is! If somebody can't handle it, then..." Here's what you're really doing when you tell it like it is.
1) Insulting people or gossiping. Fat. Stupid. Short. Ugly. Whatever. It may be a truthful description. It may not. In either case, it doesn't help the person you are telling. And it is nearly always intended as an insult. You say it when you want to hurt their feelings. What do we do with people that are like this? As much as possible, we stay away from them. Unfortunately for their families, this isn't possible.
2) Seeing the cracks in the tile. A lot of times when someone has done something wrong, the person that "tells it like it is" is the first to let them know what they did wrong, how bad it was, and to pass judgment on their character. Even if the comment is absolutely correct, and whatever happened was a dumb thing to do, the person that is first to criticize is last to praise. If you criticize how he does the dishes, next time he might just decide not to do the dishes at all. Before we criticize others for their errors, we need to make sure that we are praising or thanking them for the good things they do. You never hear someone compliment others and then say "I just tell it like it is." It would be cool!
3) Inaccurate perceptions. The person that "tells it like it is" is usually not aware of the full picture. None of us really are aware of the full picture of others' lives. We can't pass judgment on a bully if we don't know the first thing about what they go through in their own lives. A lot of the times "telling it like it is" is actually just telling it the way that we see it, and that's often incomplete. In one of my church classes once the teacher talked about a very large class that he taught, and there were two students at the back that were sitting close, writing notes back and forth through the entire class. He was very tempted to call them out or ask them to leave, and was upset by their disturbance. He found out after the class that one of the two was deaf, and the other was communicating his class to them.
4) It implies that you bring objectivity where others only see things subjectively. The person that "tells it like it is" is passing implicit judgment on others that don't tell it like it is. Usually this is a criticism of others that are too "cowardly" to tell the truth. Occasionally, I think this is partially fair, in that sometimes people don't open their mouths to defend themselves and others, or put a stop to something that shouldn't be happening, to warn others of consequences, etc. If your best friend sees you walk out of the bathroom with toilet paper stuck to you, you want the person to tell you about it. On the other hand, a lot of the time, those that don't "tell it like it is" are not telling it because they have the social skills to realize that it's not nice, it's not helpful, it's not true, or it's not worth it.
5) It shows that you don't care how others feel. Honestly, you don't have to really care about others to avoid making others feel bad unnecessarily. Just decide that you aren't going to do it. Try and track down the times and people you do it with, and stop. It's easy if you think of people you speak bad about. Just think of who they are, and then about others that "share" your opinion. Caring about how other people feel doesn't make you weak. A friend of mine and fellow Mormon has his year's supply of food storage, as we are asked to do in church. (This has been advised for church members for decades) One of his coworkers says he doesn't have to worry if the world ends, he'll just go to my friend's house, kill him and his family, and have plenty of food. He'll just lay outside his house and pick people off from afar. What the coworker doesn't realize is that my friend has neighbors, good people that are his friends, who will probably share in the food. They wouldn't appreciate someone in their yard pointing a gun at him. And this is Nevada. Practically everyone has guns.
6) It shows off your acidic and negative personality. When you meet someone that talks bad about everyone and their mother, you know that they will talk bad about you too. That's just the way it is.
And that's all I have to say about that. Telling it like it is! :)