Riddle: Die without me, Never thank me. Walk right through me, Never feel me. Always watching, Never speaking. Always lurking, Never seen. What am I?
In order to solve this riddle you need to think something that you cannot live without but you never appreciate, that you can walk through it but not feel it, that is always watching you but never speaking, that is always lurking but never seen.
The answer would be air since you cannot live without breathing, you can walk through it, it can always watch and lurk you, but you never see it, nor it ever speaks. Also, you never think about appreciating it until you experience the threat of not being able to breath.
The answer is: Air.