They say the best songs come from the heart… and I agree.
In my opinion, my personal favorite songs of mine were written during times of emotion or stress and are usually written in a relatively short time. Its for this reason that I always try to keep my trusty note book nearby. For example, the first song I released was written at a turbulent time in my life. My wife and I were having trouble with housing and employment and it got to the point where we felt like we had hit a wall. One afternoon I just sat down with all these emotions bubbling up inside and aimed it at a piece of paper with a guitar in hand. It felt like exorcising demons as the metaphors seemed to flow out of me.
Another example came when I had a heated discussion with my wife. I went another room picked up my guitar and started picking this riff and the lyrics followed immediately after, which were a play on the things we said to each other in the heat of the moment. Again another song written in the space of 20-30 minutes.
I do like writing songs around stories, but I find it harder when I sit down and try to contentiously write. I find the process takes much longer, maybe rightly so. Some times songs need time spent over them. A particular song I began writing about when my wife and I met, it took me nearly ten years until I felt I was happy with it. So never just scrap those songs you have touched on in the past, there may a use for them somewhere down the line.
Its not until I began writing songs that I came to appreciate the craft of it. Upon its release on Netflix, we watched Springsteen on Broadway. He jokes that he is such a good song writer, that he can write songs about working in factories, when he has never had a regular job in his live. Or how he can write about racing cars, when at the time he did not even have a driving license. All jokes aside, writing about your own emotions is one thing, but to convincingly tap into another persons with no frame of reference of your own, that is a skill. Especially to do it consistently. I have tried, and it is not easy.
But I believe striking while the iron is hot is a good way to go. You never know when inspiration will strike, so always carry that notebook and keep an instrument close to hand. Also never let the theme of your song put you off getting it out there. The subject may sound depressing at the time of writing, or hearing it acoustically. remember, it is a long way between putting pen to paper and fully produced track. A lot can change in that time, so write it down, work on it later.