Since the dream is supposed to end naturally with us waking up from the dream itself, how do we know what the dream wants to leave us with if something else is pulling the dreamer out of that state?

I ask because this morning I had a dream about a certain movie "How to Train Your Dragon" (it was actually a continuation of the nightmare from the night before!) but it seemed to have a positive message. I was told by either Gobber or Fishlegs (I cannot remember because I had to get up to turn my alarm off) but he had the voice of a character from another show I watch. He told me something about going to "the beach head" then I woke up from my alarm.

I'm hoping for some tips on better dream recall and how to interpret dreams that are interrupted from such things. I don't want to get upset with mom because her desire for me to get up is causing me to have issues remembering the most important part of life…well, I guess!