The vast majority of us learn very early on that we are expected to deal with facts. In and of itself this might not be such a terrible thing. The trouble starts when we combine with this the idea that we also learn very early on where these facts come from. Typically we are not learning that facts come from testing hypotheses and finding evidence for a piece of information, but rather that facts are synonymous with statements. As we have learned that facts are true, when we are provided with a statement that is held up as a statement of fact, we tend not to question it. Obviously there are times when taking this approach to dealing with the world is hugely advantageous.
"The stove is hot"
Provided with these statements and taking them to be facts our understanding of the world, at an emotional and cognitive level, adapts appropriately and we can tailor our behaviour to deal with the implications of these facts, for example, "stay away from the stove", "get a coat".
Such statements don't need to be questioned. This of course doesn't mean that they can't be, but for practical purposes taking them at face value is unlikely to cause any of us anxiety or distress. If one were to take a Gibsonian view of these statements (which admittedly is a little odd as Gibson's theories were concerned with visual perception) we might say that these facts "afford" a clear understanding of their meaning and implications. We are not bound by those implications, just as one is not bound by affordances in visual perception, but they provide opportunities and information for decision making in the widest sense, including thinking, feeling and behaving. Crucially, such statements are neutral, they are not laden with values and this might explain why we tend not to question them. However, the situation is not so simple. If we consider statements that are value laden there still is a tendency to treat them like they afford clear understanding of their meanings, and we don't question them even though there may be a broader set of possibilities behind them.
Let's consider some positive statements.
"You're performance today was brilliant"
"You have a nice way of dealing with people"
Would you be prepared to take these statements, perhaps feel a little embarrassed, but take them as statement of fact and not question them? Probably. But what exactly do they mean? What makes up a brilliant performance, and how does knowing that help you hone your skills, adapt your emotions, thinking and behaviour? Equally, what constitutes a nice way of dealing with people? Knowing what "nice" consisted of, when regarding dealing with people, you could gauge your performance and use this knowledge of your attributes in other situations. We don't tend to question the positives, but naively accept them, and in doing so we don't really learn anything from them.
Objectively this is pure laziness, but if we explore this issue a little more deeply we can understand why this laziness makes a certain amount of sense. Think about the effort that would be involved in trying to tease apart the deeper meaning of what someone is trying to communicate with these positives. How would someone react if you asked in return, "What exactly do you mean when you say nice?" How would you react if someone asked you that after you had complimented them? It feels a little strange. Just like when we ask a casual acquaintance, "How are you doing?" we don't expect to hear anything other than, "Not too bad", we expect that a compliment should be enough. You look good; you did well, great goal, what else is there that you need to know?
Social convention dictates that positive information stops there, and this means that other than being a sense of comfort, reassurance and fostering good relations, it isn't particularly functional. That isn't to say that it isn't pleasant and enjoyable, and can have strong motivational influences, but what do you learn?
Now let's get a little paranoid - how much do you trust compliments and positive statements? 100%? Do you completely and absolutely take everything positive said to you without a tiny pinch of salt? Does your critical voice ever speak up and place nagging doubts in your mind, either about the speaker, or about how their opinion might be different if they knew you better? Let's pretend that there are sometimes doubts. So, positives are not particularly informative, you can't really learn from them and you can't be entirely sure that they are 100% truthful. As far as personal growth goes perhaps they are not quite the bargain the might be. Feel good, yes, and that is powerful, but their power is coming from someone else. You haven't increased your power from them, your personal understanding of your talents, skills, biases, weaknesses etc. Someone else is in a position of power to convey these blessings upon you, and as we've begun to suspect, they may not be 24 carat gold.
If neutral statements aren't going to help us in our quest for personal growth and understanding, and positive statements aren't, the only thing left would be the negative statements.
How could negative statements help us develop, after all, the negative statements that we are so good at keeping in our heads, that running commentary that intervenes and deflates us, probably couldn't be considered to be a source of vital information that leads to our self-growth? That's true. But it is through what we can learn from the negative reactions of others - the things they say, the way they respond, - that we can start to challenge the voices in our minds, and the voices outside.
If you know what it is that you are doing wrong, you can change it if you decide to do so. The great thing is that people are only too happy to let you know what it is that you are doing wrong. Probably the only thing people like better than talking about themselves is telling other people what's wrong with them. Remember that you aren't obliged to change to satisfy anyone, but if you want or need to develop in a certain area of your life, then knowing where you are now, and how that isn't as good as required, and knowing the specifics of where you are going wrong, it's almost like you have been given a map of how to develop. Now that's a map worth having, and you're getting it for free. Whilst someone else might feel that they are getting to vent at you, you can collect useful information and use that to build up an understanding of what is expected, and develop strategies to get there.
Who is it that is benefiting, the person criticising, or the person criticised?