To dream of having a picnic represents situations in waking life where is there is comfortable carefree indulgence. Having a wonderful time thinking nothing matters. It may also reflect an enjoyable open discussion. Feeling that there is nothing wrong at all with what you are saying or doing.
Negatively, a picnic may reflect being too comfortable believing that there is nothing to be concerned with. Being naive or stupid about thinking someone else isn’t serious, angry, or, sensitive. It may also reflect your feelings about someone else being arrogant or insensitive about enjoying themselves during a serious moment.
Example: A young man dreamed of having a picnic with his girlfriend on a cliff and then getting kicked off the cliff by his girlfriend. In waking life he was openly and comfortably discussing an issue with his girlfriend who ended up not appreciating hearing his honesty and getting very angry at him.
Example 2: A woman dreamed of having when suddenly a big storm came. In waking life she was enjoying herself being heavily pregnant with her family when suddenly her water broke and she went into labor.