Okey dokey. Pineapples aren't a true fruit (meaning all tissue derives from the ovary of the plant), it's actually a combined bunch of berries. Also, people are usually surprised at how they grow, almost as if on a little pedestal.

Interestingly, the most 'fruit' fruit that people think of, the apple, is not a true fruit, either. Parts of the apple derive from tissue other than the ovary. You can see this for yourself when you cut an apple in half and notice the membrane that separates the part with the seeds (derived from the flower stalk) and the most-edible part (derived from the ovary).