I do think it is great you take the time to help them like that; I also think this isn't something you should be doing, basically taking them through a "mini therapy".
Now, granted, the line between "I just wanted to cheer them up" and "I showed them CBT" can be blurry but as soon as you take it onto yourself to actively make them better, I'd say you are strolling down a path you shouldn't. The main reason being I doubt you are an expert. The other reason being that it can affect you because you are close to them. And lastly I do not think just one such hint in the right direction is going to help the person suffering. Practically all therapists and people who have ever taken therapy will tell you just how much it feels like 1 small step forward 2 steps back, how much of a constant struggle it is. Changing a behavior is never easy, much less so if it is something that was "programmed" into you since you were a child, something that is your very view of the world. Understanding the mechanisms and a few techniques of CBT can be empowering, absolutely, but it takes so much more to actually make them work and work in the long run, to actually make you feel better and get out of that hole or to change... and not all people have that much energy or ability to introspect and watch themselves what they are doing AND then come up with ways of making it stop. Maybe in the long run it would be more helpful for them to just seek therapy?
Whilst I agree it's dangerous to attempt offering people therapy when you don't have the qualifications to back it up, I think you're conflating therapy with helping depressed individuals to recognize their condition so that they may seek therapy.
Believe me I have no desire to rescue people. Been there, tried that. However, part of the problem with people who are depressed is that they don't realise they are depressed. So when you see somebody struggling with dysfunctional thinking you have 3 options:
1. Pretend you have no additional information that can help them and hope they find the appropriate resources themselves.
2. Decide that (1) is unethical and suggest appropriate resources that may help them.
3. If (2) didn't work the last time, acknowledge that sometimes depressed individuals can be either unaware or in denial of the seriousness of their condition. Since you can't force them to seek help, you have the option of asking them the very same questions CBT taught you to ask yourself in the situation. At this point the person hopefully sees the value in what you're doing and is more convinced in the value of your suggestions in (2). At no point do you take it upon yourself to perform therapy.
CBT is based on the idea that we're ultimately rational creatures but sometimes we're not aware of all the factors influencing our cognition. While you ought to have training if you are attempting to perform therapy, you don't need a professional training to point out dysfunctional thinking in someone and point them in the direction of professionals who can perform therapy.
Analyzing, talking through, and attempting to change thought patterns isn't just a clinical technique for serious problems. In my experience, the smaller the problem and the healthier the person, the more quickly and dramatically it seems to work. Other than people who have been in therapy or who have grappled with mental health issues on their own, I rarely see people using it, with one exception: I see the parents I know using it with their children all the time to help them deal with everyday emotional difficulties such as anger management. A decade from now, there might be a generation of adults who consider it common sense and have no idea it originated in the treatment of mental illness.
An excellent point and indeed I see my experiences with depression as a strength I can pass onto my children by teaching them to recognize and handle dysfunctional thought patterns in themselves and others.
Now, granted, the line between "I just wanted to cheer them up" and "I showed them CBT" can be blurry but as soon as you take it onto yourself to actively make them better, I'd say you are strolling down a path you shouldn't. The main reason being I doubt you are an expert. The other reason being that it can affect you because you are close to them. And lastly I do not think just one such hint in the right direction is going to help the person suffering. Practically all therapists and people who have ever taken therapy will tell you just how much it feels like 1 small step forward 2 steps back, how much of a constant struggle it is. Changing a behavior is never easy, much less so if it is something that was "programmed" into you since you were a child, something that is your very view of the world. Understanding the mechanisms and a few techniques of CBT can be empowering, absolutely, but it takes so much more to actually make them work and work in the long run, to actually make you feel better and get out of that hole or to change... and not all people have that much energy or ability to introspect and watch themselves what they are doing AND then come up with ways of making it stop. Maybe in the long run it would be more helpful for them to just seek therapy?