We have a 3.5 year old and a 2.5 year old and they're both exhibiting this behavior:
They prefer to watch mommy and daddy play rather than do it themselves. I think it started with drawing, we'd show them shapes, and they'd say ask for more: "More circles!" or "More clouds!" and I thought we were doing pretty good demonstrating how to draw a shape, first with a few examples, then holding their hands, then letting them try followed by praise.
But it seemed to always follow a path where they'd ask again for more and we'd encourage "okay, keep drawing" or something like that, and then they'd say "No.. you do it!" and if we came back to help, it would repeat - as long as they were moving their hand and such, they'd be fine. So reasonably at some point we have to tell them that they can keep drawing, but we have to continue doing what we were doing.
This has spread in to other activities, where when we play, they want us to drive the cars on the playmat, etc. and it seems to be getting a little silly with respect to how often they insist we do the activity that is intended for them. They just watch. It's become so that if I want to play with them, I end up playing by myself while they watch.
On their own, they're great with respect to imagination and motivation, it's as soon as we attempt to 'join in' that they back off completely and just want to watch.
Is there a good way to respond to this? Should we stop playing until they rejoin the activity? At present if we refuse, they will continue to insist until they get bored and walk away and start something that isn't really structured or constructive.
Sometimes it is really basic things that they will stand and ask for help (such as picking something up off the ground in front of them) - I'm concerned this is learned helplessness?