Well, if everything was permanent we would have a very, very crowded world. Then it would be very, very difficult to stay here with all these people. Have you ever considered the Dukkha that could arise if things were permanent?
Some of you have heard Steve talk about how it's very nice when your loved one strokes your arm - but for four hours?! There might be more Dukkha if everything was permanent in the world.
But yes, impermanence, because of impermanence we realize that things cannot be ours. Because things cannot be ours and because there is attachment to those things, Dukkha arises. Yet actually, impermanence is not the primary reason for Dukkha. Attachment is the primary reason for Dukkha. The fact that we cling to impermanent things is the primary reason for Dukkha. Clinging, ignorance, attachment, these are primary reasons for Dukkha. This is the Second Noble Truth. Because there is impermanence and there is clinging to impermanent things, Dukkha arises.
The eight worldly dhammas, pleasure & pain, fame & obscurity, gain & loss and praise & blame, in essence these are not in themselves the cause of Dukkha. It is our attachment, either positively or negatively, to these things that are the cause of Dukkha. We have to see what's the true cause of Dukkha. The attachment and making things me and mine, that is the true cause of Dukkha.
And if we do understand the impermanence of things, impermanence doesn't have to be the source of Dukkha. We understand that pleasure comes and then it goes. Fame comes and it goes. Gain comes and it goes. Praise comes and it goes, and none of these have the capacity to give us lasting happiness. They are not the source of happiness, nor the cause of suffering. It is our reaction to these things that is the source of suffering or happiness.