Answer:
I tell people to be careful when handling boxes.
With three leaves, I am just a plant. Add another leaf and everyone will want me for good luck. What am I?
What gets bigger when more is taken away?
I am the book one can never finish reading
I regularly change shape yet remain a sphere. I am always there but not often seen. What am I?
Long and slinky like a trout, never sings till it's guts come out.