For years I was able to at least abate the depression by playing video games (almost non-stop). Unfortunately, that came to dominate my life (work-game-sleep-repeat).
When I finally got so low that I was contemplating suicide, I thought about my 2 cats who don't like anybody but me, and what would happen to them when I was gone?
There's also the fact that I don't like other people to have to clean up after me, and I'd be a pretty big mess to clean up.
I still get depressed now & then. I find looking at pictures or videos of beautiful landscapes (or driving out to them, if you can!) really helps. It reminds me just how beautiful this world really is, and it would be a shame to leave such a wonderful place. I also like seeing pics & videos of space (planets, stars, galaxies, etc.). They remind me just how amazing our entire universe is, and how far humankind has progressed (and how far we still have to go!). I want to see where we go! I may not be one of those people that gets us there, but I'm along for the ride!
I said it in another thread, and I'm still not sure I actually came up with it, but 'A single moment of beauty can light the darkest day'.