You use something to refer to a thing, situation, event, or idea, without saying exactly what it
You can use something to say that the description or amount that you are giving is not
If you say that a person or thing is something or is really something, you mean that you are very impressed by them.
You can use something in expressions like `that's something' when you think that a situation is not very good but is better that it might have been.
If you say that a thing is something of a disappointment, you mean that it is quite disappointing. If you say that a person is something of an artist, you mean that they are quite good at art.
If you say that there is something in an idea or suggestion, you mean that it is quite good and should be considered seriously.
You use something in expressions such as `or something' and `or something like that' to indicate that you are referring to something similar to what you have just mentioned but you are not being exact.