Thought Chain

When you think about something which leads you to think about something else, then that thought will lead to another thought, and so on until you are realizing what is happening.

I had a thought chain recently, it went like this:

I was thinking about sex, then I started to think about me being a father, then I started to think about my future, then I started to think about my future career, then I thought about me being a hobo, then I started to think about me dying until I wondered why I was thinking about dying. Then it all came to me...