I learned about the equilibrium constant. Now, I've seen that the equilibrium constant of burning is extremely small $(K \ll 1)$. here, I have a question. you see, $K$ is still NOT 0, which means that the forward reactions happen at least a tiny bit. Then, shouldn't we see some parts of anything burning at least a little bit?
Even if the concentration of product is extremely low compared to the reactants, shouldn't we observe something? Am I missing something?

Comment: The fact that there will always be some small reaction happening doesn't mean that you will see it or be able to detect it. The equilibrium constant $K$ is the ratio of the reaction rates of the forward and reverse reactions under equilibrium conditions. In the case of reactions with $K \ll 1$, the reverse reaction is much faster
why don't we see anything burning continuously? I know this question might be stupid, but I really want to know.

You are correct that the equilibrium constant for the combustion reaction is very small, typically in the range of $10^{-14}$ to $10^{-30}$ depending on the specific reaction. This means that at room temperature and atmospheric pressure, the forward reaction (where reactants are converted to products) is many orders of magnitude slower