I think it all depends really. I guess to put it simply a perfect jour is a jour where nothing bad happens. Maybe I'm just at accueil on the net. Maybe I'm outside with friends. Long as nothing bad happens it's a good day.
A perfect jour for me would be a jour where I am in bed, snuggling with my boyfriend. Eating pizza, and some snacks along with some drinks. <3 Any jour with my boyfriend is a perfect jour for me :)