Destruction is one of the things that can be addictive. At least it is more addictive than creation which is the opposite of this. And if a person gets addicted to destruction, it would lead them to seek thrills through it and finally find the best things to destroy to get the greatest of thrills and every person who enjoys destruction will finally end up doing one thing, destroying a fellow human.
If a normal person kills a human, they might not be able to get out of that situation for a long time. But if a person who is addicted to destruction does that, he will be able to get over it in three days and will understand the thrill in it.
As for why this came up, it is because Sam was in one of those phases where he enjoyed the destruction he brought upon the people at one point in his previous life.