When you remember an incident from a past experience, you are focusing Energy. When you are imagining something that may occur in your future, you are focusing energy, and, of course, when you re observing something in your now, you are focusing Energy. It makes no difference whether you are focusing Energy and your point of attention or focus is causing you to offer a vibration that is your point of attraction.
When you spend time pondering, remembering, or imagining something, a vibration is activated within you. If you return to that thought, you again activate the vibration. The more often you revisit the thought, the more familiar the vibration becomes, and the easier it is for you to activate it, until eventually it becomes a dominant vibrational pattern within you. And as it plays a larger role in your vibrational pattern, things that match it being to show up in your experience.
And so, there are two surefire ways to understand what your vibrational offering is : Notice what is happening in your experience (for what you are focused upon and what is manifesting are always a vibrational match), and notice how you feel (because your emotions are giving you constant feedback about your vibrational offering and your point of attraction).
Reference : Ask and It is Given. Esther and Jerry Hicks