Comment by Houshalter

I noticed that stupid jokes and stuff seem much funnier to me when I am sleep deprived. One time I pulled an all nighter and then looked at some meme subreddits. I was laughing incredibly hard to stuff I wouldn't even normally find amusing.

This seems to be a well known phenomenon. There's a whole subreddit called 3am jokes (https://www.reddit.com/r/3amjokes/) for this.