A good dream is a favour from Allaah سبحانه و تعالى because it is granted by Him. It carries glad tidings, brings happiness to the heart, and is an indication of a believer's truthfulness and righteousness. These are important reasons to praise Allaah سبحانه و تعالى for it.
In addition, a good dream should be narrated to learned people who care for the dreamer and wish good for him, so as to give him a good interpretation for it.
On the other hand, he should not narrate it to individuals about whom he may have some misgivings. Such people might become envious, belittle his dream, and even try to misinterpret it in order to cause him dismay.
Imaam al-Baghawi رحمه الله said: "A dreamer should only relate a pleasant dream to a person whom he likes (i.e. trusts). If, instead, he relates it to someone whom he dislikes, that person may misinterpret it for him out of envy, causing him some distress. He may also try to plot against him, Allaah سبحانه و تعالى described Ya'qoob's عليه السلام concern regarding his sons' plotting, should Yoosuf عليه السلام have related his dream to them."  
Therefore, upon having a good or pleasant dream, a person is urged to take the following actions:
(1) View it as a good omen from Allaah سبحانه و تعالى.
(2) Praise Allaah سبحانه و تعالى for it.
(3) Narrate it to those whom he likes and trusts.
(4) Avoid narrating it to those whom he dislikes and distrusts.
(5) Seek its interpretation from learned people with good knowledge of dream interpretation.