I didn't believe it would have a mental effect. I assumed that was placebo affect or simply a better mood/mindset stemming from a change in the right direction. It has been a few weeks now since starting HRT and the anxiety is next to nil.
The closest thing I can think of to relate it to are those things you have to train your instinct out in order to perform i.e. posture/hand positions for playing instruments, turning into a slide instead of away to avoid a crash, not having your arms break a fall, heck as simple as chewing with your mouth closed. They all become habit with training, but will never completely feel natural. It's like that type of habit applied to every aspect of life in how I perceived my environment and how I reacted to that environment. Then, instead of all those basic thought processes being trained habit, it became natural, instinctual. Funny though, my thoughts, emotions and reactions haven't strayed from pre-HRT (yet), they are just far less taxing to maneuver.