Once upon a time, a long time ago, there were a young woman and a young man who hung around together in college. They were friends. They acted in plays together. They even made a really cheesy student film together, and had a ball doing it. They were funny together, playing off each other's strengths like a good comedy team. Most of the time they got along well. Sometimes they didn't. Occasionally they wrote stuff together. Then the young man graduated from college and got married and moved away, and the young woman moved away and started working and moved back and met her sweetheart, and she got married too. And all this time the young man and the young woman stayed in touch, because after all, they were friends.
The young man kept writing stuff. He had written comedy in the past, but he decided that now he wanted to do something serious. A screenplay. So for three years, more or less, he worked on a screenplay. When he was done, he sent it to the young woman. Some of his other friends had already read it and told him they loved it, but he wanted her to read it. He told her he wanted to know what she thought. Her opinion was important to him. He told her, in fact, that he wanted her to be brutally honest.
So the young woman read the script. And as page after page went by, she realized something: this script was bad. Not just a little bad, but really bad. It was facile, anachronistic, and the key scene of the film was simply unbelievable. There were so many problems with it, in fact, that she was certain the script couldn't be salvaged. Either it would need a complete rewrite, or it would have to be scrapped altogether as unworkable.
But what could she say to the young man? She knew her friend had spent three years writing this script, and it meant a lot to him. But she also knew he wanted it to be successful. She could not, in good conscience, lie to him and tell him it was good, when she knew it wasn't. Besides, he had told her to be brutally honest.
And so the young woman was brutally honest with her opinions, and the young man was furious. He contacted the young woman to defend every single story choice he'd made, one by one. He reiterated that he'd spent three years of his life working on this script, and that she had no right to tear down that work with her words in just a matter of days. He told her angrily that he was going to send the screenplay to a professional critiquer and see what he had to say about it.
The friendship did not survive the experience, since the young woman officially severed her ties to the young man. Neither did the script, since the professional accepted a generous fee to read the screenplay only to arrive at much the same conclusions as the young woman.
So what should the young woman have done? Should she have turned down the chance to read the screenplay? Should she have followed Thumper's Law and refused to say anything about it? Or should she have lied to her friend, telling him he'd done great work just for the sake of keeping the friendship on an even keel? How do you determine when people really want your honest opinion, and how do you tell that apart from times when they claim to want your opinion, but really expect to be petted and praised? If you can give surefire answers to these queries I will personally nominate you for the Nobel Peace Prize.