Just because someone is depressed doesn’t necessarily mean that they’re down and sad 24/7 (this isn’t applicable to everyone with depression). They can still have good days, and if something good happens to them, they can still be happy about it. Also, this doesn’t mean that when they’re happy, they’ve gotten over their depression. Some people might be faking happiness so that others can’t tell their depressed, but just because someone is depressed doesn’t mean that they have to be sad about everything, and if they are happy about something it doesn’t mean “they’re not REALLY depressed.”