The best feeling I've ever had was when I was in real love for the first time. I wander if you could make a dose - In Love - that makes you feel like you'r in real love again:
Feeling butterflies (tickling) in one's stomach, smiling (but not overwhelming laugher, just smiling), happy, everything looks so friendly and nice, and a smaller adrenaline rushing throung one's body. The power of the dose could be moderate or strong - it doesn't have to challenge the limits of your feelings.