I have not logged in for a very long time, but this conversation definitely took my interest.
There can be an actually psychological point to this game that can create a large amount of strategy to it.
I have been playing since around the time legend maker was released and have done well since then as well as creating my own psychological strategies.
I'm quite skilled at rapid memorization and math. This allows me to quickly produce ratios and probabilities in my mind of what is possible and not possible for my opponent to do during their turn as far as cards played, drawn, and returned. This isn't the psychological part, but it plays in.
Being able to do that kind of calculating allows me to relax a bit when playing during my turn. When you relax, your opponent may get nervous. You have to remember that not only are you reading your opponent THEY are reading you. If you have enough self control you can actually manipulate your emotions to match what you would like your opponent to see.
In more than one game I have manipulated my own facial expressions to seem as though I was feeling the very opposite of my opponent. You must also have a great knowledge of your facial expressions and your entire mannerisms. A good knowledge of your body can have huge psychological advantages in this game. You can make yourself seem bigger or smaller depending on how far up you sit in your chair. Opening your eyes a little wider may make you seem quite intent on something you or your opponent has done. Even the littlest thing such as shifting in your chair a slight bit after your opponent has made a move can make them question it.
The list goes on... Certainly psychology can win you games, but you can't build a 60 card deck out of body language that's for sure.