Restlessness is discontent and discontent is the first necessity of progress. Show me a thoroughly satisfied man and I will show you a failure.
But I think the children of actors share a certain pragmatic approach. One is denied some of that 'running away with the circus' element of being an actor.
There are many talented people who haven't fulfilled their dreams because they over thought it, or they were too cautious, and were unwilling to make the leap of faith.