Realization that no one else will be contributing
Realization that programmers capable of really contributing probably think "filing a bug" was "contributing" and will bug you about timelines
Realization that people in paid jobs are pressuring you for bug fixes and feature timelines
Realization that being asked for free support from perfectly nice people has a mental cost, either in not providing it, or in providing it
Realization that open source zealots will judge you, and companies will avoid you, if you choose any other license, but at the same time, none of the problems above have solutions...
Feeling that your work provides charity to for-profit enterprises
Ennui/Abandonment: A strange game. The only winning move is not to play.