Well, in my opinion, the only mental block is the one that you have created from living up until now. It isn't there on purpose, it is just what everyone has to get over in order to ld, because with every night that you didn't try to LD before learning about it, and with every night you didn't try to LD since learning about it, the wall gets bigger. Of course every time you practice LDing you start breaking down the wall, and the longer you practice without taking a break, the more easily the wall will break down.

So as you can see, with my wall analogy, you must be consistent, and don't think of anything being against you more than it is against anyone else, the biggest mental block is the one that you think is there. Haha. Here is a thread I made about mental blocks and techniques.
http://www.dreamviews.com/dreamviews...technique.html

Good luck with your lucid endeavors. Don't forget to practice the fundamentals. Recall, awareness, and sleep schedule! If you keep working on them every day, you will continue to get closer to LDing bossery.