The first comment I want to make is about dreams: Dreams generally as they are portrayed in Tanach and the specific dreams of Yosef in this parsha.
It is striking to me that while Yosef seems eager to relate his dreams to his brothers and his father, he does not offer an interpretation. However, the listeners all seem to think they understand the meaning of the dreams. For his part, Yosef does not dispute their interpretations. But it is interesting that Yosef's whole career later in Egypt is based on his ability to interpret dreams and he does not display that particular talent here.
We saw earlier at the beginning of Parshat Vayetze that Yaakov has a dream. There is no clear interpretation of that dream set out in the text, thus giving rise to many midrashim and commentaries.
It is also interesting to note that the term chalom (dream) appears in the Torah only in B'reishit (Genesis) and much later on in D'varim (Deuteronomy) where it is written:
דברים פרק יג:ב
כי יקום בקרבך נביא או חלם חלום ונתן אליך אות או מופת...
When there will arise among you a prophet or a dreamer of dreams and he will give you a sign or wonder...
This latter case is about a false prophet. The implication is that dreams can be a manner of prophecy, false or otherwise. This fits in with the way dreams play out in the story of Yosef and also serves as a basis for possibly understanding Yaakov's dream methinks.
What is tricky then about dreams is that they are not necessarily straightforward in meaning. This comports with human experience. We all dream but even if we remember our dreams we tend to notice that often the dreams don't make sense or don't fit in well with a reality we are familiar with; we can dream about things which would be impossible in real life.
Why doesn't Yosef tell his brothers what he thinks the dreams mean? What does he gain from telling them (and his father) at all?