BigFoot

Riddle: People make fun of me for being too small or too big. My human calls those people 'bullies' and cries when he goes home. I am very spacious. People share their most wonderful and most dreadful memories, thoughts, opinions, plans, deepest darkest secrets, most embarrassing moments, and the saddest of moments. People trust me to keep their secrets, though they never really tell me them. Whenever anything happens to a person, I am the first to know about it. I am the most loyal and truthful friend of a person. I never go away unless specifically removed. If I go away, people can tragically die. I never make fun of anyone even if I hold their most embarrassing secrets. I'm the source or core or holder of a person's suspicions. I can never be lied to. I always know the truth. I know if a person is sad or happy or scared or nervous. I am gifted to only so many people. What am I?