What conclusion did Gregor come to after his first night sleeping under the couch?

Gregor decided that he must have great patience and show immense consideration, so that his family could bear the unpleasantness of his condition.

He spent the whole night there. Some of the time he passed in a light sleep, although he frequently woke from it in alarm because of his hunger, and some of the time was spent in worries and vague hopes which, however, always led to the same conclusion: for the time being he must remain calm, he must show patience and the greatest consideration so that his family could bear the unpleasantness that he, in his present condition, was forced to impose on them.