|OK, you've sucked me into it again, goddamnit.
I used to think that way too. Talking to buds can be therapy. But, there is an objectivity issue that impedes, for one thing. For two, therapy involves, go figure, a disciplined approach, and training. Therapy is aimed at a result. A buddy can empathize, he can give a certain amount of advice, but a true therapist he is not. A buddy is not where you go if you have a deeply-seated trauma that has been on you for years- you can't expect him to help you fix that.
Look- some people do not believe in mental illness, despite what you see from one end of things to another out there. They might think you can just figure it out for yourself. I'm not going to address this, to me it doesn't bear addressing. I think I.N. Rand covered that with great clarity for the purposes of this discussion.
A simple idea, it's really just William James 101: The power of an experience. Say that you had an unpleasant incident with someone, you were very upset. The fact of it is that even years later it is possible to recall this incident and have an even more powerful emotional reaction to it than you first did. This is a true thing that happens to people all the time, this cannot be argued against. You can be a clear, rational, moral beyond reproach Objectivist, with kick ass ethics and even better aesthetics. A is always fucking A as far as your eye can see. And yet, this can happen to you. It very bloody likely has happened to you, because that is how human beings are wired up. This is clearly a subjective situation! Yet, it causes the pain. Picture many, many of those, of various magnitudes, built over a long period of time. This type of situation is one where a therapist can be of great use. You cannot always objectify it. It is too much, sometimes.
I'm just giving one, simple, basic idea here.