A question on psychology / strategy in Chess opening Is it a good idea to play unusual openings (minus the d&amp;e files), such as c4 played by Bobby Fischer in his “Game of the Century”, to confuse the opponent and stop them from playing their natural opening in the rated tournaments?
There are many ways of looking at this depending on one's strength. Super Grandmasters are able to shift between openings with ease and still play them well at a very high level and with deep understanding. As for middling players, it is good to stay with one opening line for long and there are several advantages to that; 


Experience is a very important aspect in the road to mastery and there's no shortcut to acquiring experience. The great martial artist, Bruce Lee once said, 



  I fear not the man who has practiced 10,000 kicks (chess openings) once, but I fear the man who has practiced one kick (chess opening) 10,000 times.


The same could also be said about chess and sticking with one (or a few) opening lines for long time, acquiring more experience, deepening your understanding in strategic &amp; tactical ideas behind the opening and both the resulting middlegames and endgame positions.  


Don't play against the player but play against the pieces. Most great masters of the past including Bobby Fischer himself have stayed with one opening repertoire for long and playing fearlessly against all their opponents. Fischer played just a few openings, Ruy Lopez, Sicilian Najdorf, King's Indian Attack &amp; Defense, Grunfeld Defense, and others in between. Some openings and variations have been named after masters simply because they remained loyal for long and built indepth understanding in those lines.   
The desire to win quickly and the creeping in of last minute doubt in one's opening repertoire is what has led many players to run away from their main weapons, hoping that the new unknown opening will yield better results in their favor. More often than not, it is the same players that end up surprising themselves with their own lack of experience in the new unusual opening than surprising their opponents. The sad is thing is that after the game, there isn't much to analyse or to add to your experience in that surprise opening.


For serious tournament games, I would strongly recommend sticking with one's main opening repertoire and using surprise openings for blitz and casual chess. As for beginners, I would recommend that they should stay with simple openings that adhere to basic opening principles (develop your pieces quickly, knights first, king safety, etc) like the Italian Game before trying to surprise anyone.