Most serious martial artists know that once a practiced technique (or series of techniques) become an automatic reflex, then that's when they are truly available for your self defense, and they become a reflex after you've been practicing a good long time.
For some serious, heavy theory on, not just martial arts, but what your own attitude, expectations, and purpose should (or must) be, get a copy of Stephen Kaufman's translation of the Japanese classic,
The Book of Five Rings, by Sensei Miyamoto Musashi.
Musashi was the "Sword Saint" of Japan, and although he killed guys for a living (Samuri) he was very religious and philosophical about it.
His book is full of thought provoking wisdom, like he says "You can only fight as well as you train", and "I really must insist that constant training is the only method to achieve the way of the warrior", and he can surprise you with this reasonableness, like "there is nothing wrong with withdrawing quickly from a situation if you believe that you truly cannot win", and "when fighting against a group, identify who is the loudest and most violent, and defeat him first, the move on to the next most violent, the next, and the next. keep your center moving and do not allow yourself to be surrounded by them or they will overwhelm and defeat you."
And there's lots more, it's just 100 or so pages long, but reads like your grizzled old Pa telling ya like it is. Some months I try to read 10 pages each day for the first 10 days of the month, it's the kind of teaching you can read over and over and get something more each time (which he himself states). He constantly stresses that the sole purpose of using martial arts is to destroy your enemy at the time it is necessary, any attitude less than that is flirting with defeat (very Japanese mentality, no?)
I, for one, found reading the book greatly improved my technique in every way, not because he addresses techniques (he doesn't) but because you're just so damn serious after reading it that you do everything with more conviction and energy.