To dream that you are in a laboratory suggests that you are experimenting with your inner feelings, beliefs, or fears. You are testing yourself or some relationship. Alternatively, being in a laboratory means you are going through some sort of transformation.
To dream that someone is leaving you refers to feelings of rejection or of not being able to keep up. You are questioning your abilities. Perhaps you are not utilizing your full potential. Alternatively, the dream indicates an end to something; you are ready to let go of the past and move forward.
To see silly string in your dream implies that you are trying to divert attention away from a problem. You are covering up your true feelings.
To see or throw a hand grenade in your dream represents pent up anger that is ready to explode at any moment. You are no longer able to contain or repress your emotions.
