Daydreams are an elaborate, and deep form of imagining or visualising. These can be powerfully used to your advantage if you construct an elaborate complete visualisation 'dream sequence' which emcompasses what you wish to achieve -- Jon Peniel
Affirmations and visualisations are very powerful and must be respected as such. An affirmation or thought is like a seed -- governed by the universal law of cause and effect.
'what you sow you shall reap'
Thus, affirmations should always be consistent with spiritual purposes and ideals. Also, it is better to use affirmations and visualisations only for development of positive traits, and for positively changing your subconscious programming. Even then it should be done with the inclusion of a 'conditional' affirmation:
'only if it is within the will of the universal spirit'
It is not possible to know what is really best for a given situation, and it is possible to cause problems by using an affirmation or visualisation to do specifically what you ascertain to be right.