Of the four directions, east is the most sacred for orthodox Hindus. The ancient Indians believed that one magnetic field passes from the south to north and another one in east to west directions. The latter force field is considered essential for the sustainance of life on earth. They are analogous to the modern day longitude and lattitude. Based on this, Hindus give a lot of importance to the directions while doing day to day activities.
While sleeping, it is okay to keep the head towards east. After waking up, turn towards the east and bow to our parents, teachers, look at both palms of the hand (and chant the Karagre vasate lakshmi.. mantra). Touch the ground and touch the forehead as a symbol of paying respect to mother earth.
It is while facing the east that one should light the sacred diya (deepam / oil lamp). The sacred plants like tulsi, neem, jasmine etc should be planted facing the east. The entrance and the front side of a house should be ideally facing the east. If you have idols in your courtyard, they should be ideally facing the east. Most of the sacred deeds are done facing the east. The bride garlands the groom facing the direction of east. If the well or pond faces the east, it will get lots of sunshine and the water will get purified by the sun's rays. The ideal place for cowshed is considered to be south-east.
It is not good to have toilets in the east direction of one's house. Also because of the sanctity of the east, it is not good to dump garbage and left overs in the direction of east. We need not think a lot to infer that it is not good to do excretory functions like defecation and urination facing the sacred east. It is said that even if one faces the east while brushing one's teeth, it is better to spit in the direction of north avoiding the east.