Where do your thoughts go when あなた are alone with nothing to do for a long time?

Well, they are スプリット, 分割 into three points.

The first, is the past for me too. The Life I have lead till now. Certain people and experiences come to mind that might make me feel pretty nostalgic または the exact opposite.

The second, has to do with my future. Various possibilities on how it could develop クロス my mind.

The third, is Fiction. Sometimes it might be getting mixed with reality as well. Mostly make-believe scenarios about my Life, Series that I am a ファン of または simply the World in general. There are no limits here so it consumes the biggest amount of my time as well, I believe. It is quite easy to get ロスト in its vastness.

All those three contribute heavily into getting quite Philosophical at that moment !!!!

Usually to messenger where I proceed to spam Riku with literally every thought that crosses my mind. See it counts as being alone cuz she doesn't respond right away.

Rarely anywhere good

Depends on my mood.

Sometimes my thoughts go to a really dark place.

Sometimes I replay happy moments.

I rarely put much thought into the future, they're もっと見る fleeting thoughts.

Sometimes I'll think about 映画 または shows I've watched recently.

Then other times I'll think of hobbies I should take up but never get around to :v

65% of time my thoughts go into analyzing what I`ve done and what I should improve, in terms of health, lifestyle and 全体, 全体的です to become the person that I`d really want to be.
25% goes of nostalgic, happy moments.
Then there are 5% of 'oh god, why' moments.
And 5% of something else, unrelated of anything. ^_^

(I`m not mentioning those times when I think about different plot points and twists to any of the stories I`m writing, because I`m counting that as something I deliberately plan on doing beforehand)

I daydream. I kid あなた not, I daydream so much I daydream in my actual dreams. I could be dreaming about being able to fly and I'm still 空想 about the latest fanfiction I read in my dream.

I also like to rank/organize everything I like. お気に入り bands, お気に入り manga, お気に入り tv shows, etc. If I don't know the order I just alphabetize them in my head. I do this on a daily basis.

When I do something particularly weird/embarrassing and I have time to myself, I also try re-enact other people confronting me about 発言しました situation and me explaining myself, so if someone does try to talk to me about it later I know exactly what to say.