Yeah completely understand that. I smelt some in store (this was months ago), put the vanilla one on my wrist...thought it was absolutely disgusting & was annoyed at the fact I was going to have to walk around smelling like that. But hours later I smelt my wrist & it smelt so good! They completely change once on. :s
That is because perfume or fragrance is composed of three notes ; head, heart and base.
http://www.howtosmellawhale.com/perfume-101-the-3-parts-of-a-fragrance/