Last time I saw this comic, somebody complained that the door lock is reversed. Before locking it, it's horizontal (usually closed), and after locking it, it's vertical (usually open). This observation makes sense to me, but it also made me pay close attention to all door locks I see, and I realised that the toilet at the gym is just like the door in this comic. I will never be able to live normally again, and now that I have shared this knowledge with you, neither will you c: