We got Elizabeth a bicycle for her birthday -- she had outgrown the 12-inch one she had, and so we bought her a new 16-inch one. I spent about 2 hours putting it together on Saturday only to find out that I couldn't get the pedals on. Apparently when they made the bike they forgot to thread the holes that you screw the pedals into -- so it couldn't be assembled.
We took it back to Toys R Us and they said they hadn't seen one like that before. Of course, the one we got was the last one they had. Luckily, we were able to get them to give us the floor model and without charging us for the assembly of it. So in the end it turned out ok, but it was a waste of time.