Often (always), little kids want to do things that they see their older siblings doing, but they just physically *can't,* and then they get frustrated, and then there is screaming... so much screaming.
The 123 line from our favorite Playmobil is awesome because it plays like a Big Kid Toy, but there are fewer pieces to keep track of and no choking hazards, which makes it perfect for ages 18 months and up!
There is something super fun about putting the little astronaut inside the rocket and then taking him out again. Can't explain why, really. You'll just have to experience it for yourself.