Like Maggie, we got stuck in sand, with miles between us and help. We had a Fiat, and my dh picked up the front (engine was in the rear) and moved us to firmer ground. He also told me I couldn't catch a crab with a net. Yeah, hehehe, it was a beauty.
But the best trip was on our honeymoon. The first night was spent in a motel in Needles, California. There was sand or grit on the floor, so we had to brush off our feet when we got in bed. Then, the mattress sunk in the middle and we rolled in the center together, you had to pull yourself out of that crater, but we were honeymooners so it was fine.
The next morning we stopped at a small Cafe and our waitress asked us if we were newly-weds. We told her we were and she stated that she was too. I always wondered how she could tell. Maybe we looked happy.
Later on the trip as we passed through the Painted Desert, it was hot. Very hot. My car had a non-working air conditioner, but I flipped the switch in desperation, and it worked! It was the only time it ever worked, but was nice as we rolled up the windows. It's a moment that we've always remembered.