Some people also fall into what I call the tranquillity trap.
They think that meditation is all about tranquillity, so they do lots of sitting meditation and follow a quiet, peaceful lifestyle. They may even eat less and be less active. They notice that when the body calms down the mind calms down, and when they see some results, they adopt this as a habit.
However, often the mind calms down not because of some positive development of concentration but rather because of lack of stimulation. When the mind is undisturbed by the body, it seems to be calm. But while the mind may be tranquil, it is often also lacking in clarity or energy. This kind of calm is closer to lethargy than to vibrant tranquillity.
Also, there is the danger that the body may start to break down due to lack of exercise or attention or proper care.
This reflection by Ajahn Thiradhammo is from the book, Working with the Five Hindrances, (pdf) p. 120.