Why do I lie? I need opinions.?

I have a hard time telling the truth to people. I can't even tell my boyfriend what time I go to bed. Even when my parents or anyone else knows the truth about something that I lied about, and they are basically begging me just to tell them myself, I just lie and subconsciously choose to disappoint people. I don't lie about things like, "I have lots of money and live in a mansion.. blah blah". I just lie about little things. I don't want to hurt anybody, but I know I hurt the people who I truly care about.