Sometimes as a parent you´ll get annoyed with all the little pieces lying around, but fact is that a Lego session can chase away both thoughts of work on a Sunday morning and breakfast hunger.
I did these cars with my boys this morning, and we have raced them too. They work fine after some adjustments. And the sound when rummaging for Lego in a plastic box is still the same as when I was a kid. Some things don´t change. :-)
So, an advice for annoyed parents; Get down and play instead!