A common symptom of depression is usually called something like loss of capacity to enjoy pleasurable activities. For instance, over the last few months, I have had less enjoyment from playing the guitar, from listening to music, and even from cooking.
The irony is that these are activities that I engage in not only because I enjoy them for their own sakes, but because they are calming, soothing, even meditative. They relieve stress.
Instead, I've felt like it was worthless for me to play the guitar (because I'll never be a great guitarist), and I haven't been listening much to music (because I can't ever figure out what I want to hear), and I have felt like my cooking was in a rut (because I haven't been patient or exploratory). The distorted perception related to my depressive outlook discounts the value of the activities that generally do, and generally should, make me happy, and so the prospect of them is sometimes overwhelming.
For several years, I found an hour every day to play the guitar (guitars, I suppose), but lately I practically force myself to play, sometimes just out of guilt that I own them and they just sit there taking up space. As one might well imagine, playing an instrument with that motivation is not all that enjoyable. It also doesn't lead to the best performances, which reinforces my perception that I'm so lousy at playing that it's not worth it.
My Loveliest will say that I play beautifully, that she loves to hear me play, and that what should matter is that I play because it feels good to play. This is a difficult message to understand, because I can't think about it in terms of what it does for me. Instead, I feel stressed.
So, the activities in life that I enjoy, that, in a manner of speaking, I need to enjoy, are not relieving stress, but causing it, because I am depressed, in large part because of stress.
Ergo, depression is stupid.