Whether it's ritual or habit are just as essential to the process as anything else. Although I'm sure many would make the distinction that ritual is spiritual and habit is more mundane, bottem line is they're the same, in both good and bad. A habit such as driving w/o a seat belt can be just as detrimental as a ritual that requires you to dance naked before a full moon in below zero degree weather. On the same note it can be very helpful in the same effect. Turning the temperature down or dimming the lights give the same effect as the day turning to night and gives the mind the impression that it's time to sleep. (This can be very helpful if you're trying to get into a medative state) Putting the spiritual aspect aside, biologicaly, dimming the lights, lighting incense, or playing music all have an effect that can be used for desired purposes. And if you want to bring it to the mundane level, we have rituals (habits) that get us in the motive to do our desired chore. Putting on shoes to go outside, opening a book to read, picking up the phone to make a phone call. It is just up to you whether your habits are effective(dimming the lights), pointless (speaking in a tounge you don't understand) or harmful (cutting yourself).
*sorry if I've just repeated what's been already said, just felt like I needed to put my own take on the subject.