How come my neighbour got a certain item from an adventure and I didn't?

The items that you get from an Adventure is a bit of a lucky prize dip. You'd get a chance of getting up to 5 times the money you paid (it can also be less). You also get a chance of Energy, common items, rare items and some adventure only items.

If your neighbour got something you didn't they were just lucky on that try. Keep trying and you could get something good to.