Introspection is looking within oneself, a type of meditation.
It is a thing which is radically lacking in modern life due to our addiction to the distraction of mass media (especially, recently, 24/7 social networking facilitated by mobile phones and other personal devices that are carried or worn); and also due to the sheer busyness of modern life.
I regard introspection as necessary - but it does not necessarily do us good; it is potentially valuable rather than intrinsically valuable.
Whether introspection does us good, or ill, depends upon things like:
1. The aim or purpose.
2. The content of the mind which is being introspected.
3. What scope or validity is allowed to introspection
For example, if introspection is undertaken for a wicked or ignoble purpose, then it may harm - likewise if the memories being examined are bad in some way or if the imagination being deployed has been corrupted. And if introspection is regarded as yielding only trivial entertainment or illusion, then that is all it will yield.
In sum, if the mind it filled with bad things - or has been corrupted in its operations - the introspection may have bad results.
So, there are assumptions about the potential benefits of introspection - raging from regarding it as essentially trivial and optional, up to regarding it as potentially one of the most profoundly important activities a person might engage in.
1. Pleasure, diversion, entertainment - introspection is just a means of temporality distracting oneself; like watching a self-generated movie or soap opera, or engaging in wish-fulfilment fantasies.
2. Therapy - introspection is assumed to be necessary for good mental health, perhaps as a balance to action. This sees the purpose of life as elsewhere, and introspection a means to pursuing this end - rather like a psychological pain killer or tranquilizer.
3. Knowledge - introspection is regarded as potentially yielding true knowledge (which will presumably then by checked or validated, like any other potential source of knowledge).
4. Spiritual knowledge - introspection is regarded as the only method for attaining certain kinds of spiritual knowledge. This entails that some kinds of spiritual knowledge are located within the mind (and nowhere lese) be regarded as a real thing, and not some kind of delusion.
5. Spiritual experience - introspection is regarded as providing some kind of real experience, potentially life-transforming. For example, it may be regarded as a way of tapping into special powers, or a divine essence.