For every triumph like LEGO Ninjago or LEGO Friends, there's been something like LEGO Time Cruisers or Galidor that kind of shit the bed.

Back in the day, I didn't know for sure what I wanted out of my LEGO hobby. If a new set looked cool, I wanted it. The theme didn't matter.

Turns out, no. They're not. Actually, they're kinda neat.

The short, and perfectly definitive answer is: NEVER