Answer:
I tell people to be careful when handling boxes.
When I come in from sea to shore twenty paces you'll see No less no more.
You see a boat filled with people. It has not sunk but when you look again you don't see a single person on the boat. Why?
Drop me and the world will shatter. You can always find me where you empty your bladder.
When you stop and look, you can always see me. If you try to touch, you cannot feel me. I cannot move, but as you near me, I will move away from you. What am I?
Runs over fields and woods all day. Under the bed at night sits not alone, With long tongue hanging out, Resting at your feet until we go for a walk