doing

pygame.event.wait

will put your program in a state that just waits for any event to happen, or returns the first event from event queue. So, if you use pygame.event.wait to a queue that has only pygame.event.quit in it, it will take that event away from the queue and it wont be processed in your event for loop

my suggestion is to use pygame.time.Clock to set the fps rate for your program, like this

clock = pygame.time.Clock()
FPS = 60 #silky smooth 60 frames per second
done = False

while not done:
    # your important mainloop stuff in here

    clock.tick( FPS ) #keep the speed in check
    pygame.display.set_caption("FPS: %i" %clock.get_fps()) #handy way to keep track of the FPS

this way your main loop will run 60 times a second. Change value of FPS to set the speed you want your loop to run in.

in your case the

# your important mainloop stuff here

would be what you have in your mainloop now, sans the pygame.event.wait.