Why do people self sabotage?

Why do people self sabotage?

Is it fear? Fear of success? Fear of failure? Depression?

For example: I am suppose to take my medicine daily, and sometimes I just don't take it. I use to be very good about it, but now it's like I am too tired to take it.

Another example: Or people who procrastinate to the point that they never get anything done.

It's sabotage! What are your thoughts on this?
Why do people self sabotage?
Post Opinion