Mixed Dreams

I don't know whether it happens with me or everyone but this happens to me every time. whenever I dream it's not a single thing always some phases of my life are mixed. I mean the thing which is somehow impractical... and if it is soi then why do I dream  that??

I read the theories saying that dreams are the things which are going in your sub conscious mind. But why would such thing will go around my mind. Let's take an example last night I dreamt that I've lost my phone now the point is I lost my phone which I had brought 2 months back and what I dreamt was I lost it in my college when I was studying with my school friends..... How can it be possible?? This is just another impractical situation.

The above was just an example, my point is whenever I dream I am not sure what it's all about. Theories say that it's dreams are the thoughts of your sub conscious mind. But why would my sub conscious mind would think so???? It might be a fear of loosing phone but where do other things came?? like I was in college studying with school friends.... I just couldn't get it....Si I would call them Mixed Dreams 

This is not just only once whenever I dream always the situation is ambiguous. I am always surprised after waking up what it was?? On this note I am closing my post right now.... will see ya guys later... by the way did I missed saying

GOOD MORNING