That's happened to me often. I went with my sister last year to look for a van for her - I bought one, she didn't! I once went to buy a gas mantle for my ancient Sprite and came back with a much newer one.
Buring our first camping trip nearly 6 years ago during the May Day Bank Holiday the OH said in passing "I wonder what caravan our car can tow? It does look much warmer than camping."
Six weeks later we were driving back to the same site in Dorset in our brand new Bailey Ranger.
Yes similar thing to us, going past the dealer ship the kids needed the loo, knowing it had a toilet we called in and came out with a new Adria 4 years ago. Dearest loo visit ever me thinks.
Ah I have a new business idea now shoes and handbags in the shape of caravans.
Then again perhaps we should all pose in front of the van each morning with our best shoes and handbags. Passers by could give points out of 10 for style and caravaning usefulness, they could make a TV program about us!
It would be much better than strictly come dancing!