Scientists who study dreams say that the last five minutes of consciousness in the day determine what we dream about at night. Likewise, the way we sleep greatly influences how we function the following day.
This is a good reason to recite the Shema before going to sleep; it is in the prayer books.
Essentially, it's a time for reflection on the events of the past day. It's also a time to analyze what needs to be corrected for the next day, as the Hasidim used to say, "Tomorrow will be better," meaning that one will improve oneself the next day.
The prayer ends by entrusting our soul to God during the night and asking Him to take care of it and renew it, to give it a new opportunity the next day.
I feel that prayer is slowly transforming me, and it's a wonderful discovery.