There's lots of theories in this thread, and out there in general, but it's worth noting nobody actually knows.

That's the answer to most brain questions. We've been trained to think information is just a duckduckgo away, but there still are some unknowns in science.

Dreams are the brain firing neurons in memory circuits without running the parts that correlate your mind's contents or try to keep things coherent. This strengthens and reïnforces memories by essentially exercising the neurons, but having them fire without the safeguards naturally leads to chaotic and bizarre perceptions.

I noticed my dreams get more hectic and urgent if I have to pee. If I get up, relive the bladder and then go back to sleep it's sweet dreams again.

But I wish I could remember my dreams better. I wake up convinced I could write a banger of a novel some days. But they're gone so quickly from my reckoning. The brain is such a weird thing.

If a dream were crazy, I'd actually be motivated to think about what it means.

I thought I'd do some Jungian dream analysis on myself, so I started trying to remember my dreams.

Turns out, they're all the same: I'm at some job in some place with some low grade anxiety because I'm incompetent.

So much for my hero's journey.

I had a dream about a rescue shelter for hot dogs. Like you could adopt one. They even had little pages on their web site and everything.

dreams that don't make sense one bit.

Nearly all dreams are this kind, at least after you wake up and switch on your rational mind.

I recall reading somewhere that the emotions in dreams are more important (and correlative to real life), thus what to focus on rather than the facts.

I don't think dreams necessarily have meaning. They /can/ be about things you've been thinking about or stressing about. But I think their internal logic means little. I've had some which were total nonsense. I suspect it's more valuable to look at the emotions which were being experienced during the dream than the plot itself.

I forget them after 5 minutes.

The most interesting theory of dreams I’ve read is that they provide your brain with “out of training” data so it doesn’t over-fit to your lived experiences. So your brain stays open to the possibility that completely unexpected things could happen.

I watched a video on Paul McCartney as a bassist and video on Yeti. That night I dreamed of Paul in pigtails singing to a yeti.

There have been dreams that have been made of perfectly sensible things, but have been so ludicrous in combination that I have woken up laughing.

... but usually I enjoy looking at signs with writing on them because they never stay the same when I look away and look back.