I guess it's fair to answer my own questions.
I cannot remember a time when people called me boring but I don't think I've been described by others in a particular way anyway.
I feel boring. I am unexperienced (which is not a synonym but clearly a factor). I also feel I lack passion. I feel pretty ordinary or average, even conventional. I'm also stuck in my comfort zone. Of course I want to feel exciting, fascinating, interesting, different, complex and eccentric. When I complain about it with friends, they of course tell me I'm not. Complaining is useless, I have the power to spice up my life. I guess having low self-esteem and depression are good explanations. It feels unnatural, because it's just a reaction, when I say my curiosity is endless, that I'm vividly imaginative, that my mind is fascinating or some other thing like that. I guess I have a tendency to sell me short. Now, while posting this, I'm not brooding about it but it comes and goes. There are moments when I really feel worthless.
My type is in my signature. My Jungian type (specially N vs S) is a mistery and, to be honest, partly because of this issue. I know it has nothing to do but I tend to idealize things too much that I'm unable to relate to them and I am so aware of this fixation that I also don't want to deduce anything from it and use it as a cheap trick to deceive myself, letting me pretend to be what, genuinely but pathetically, I don't know if I'm objectively not (I don't know if I don't know for the same reasons). I feel like I'm barely making sense.
Thanks for the answers so far.