What do you think of the theory that cheese affects your dreams? It's definitely true imo, blue cheese in particular. If I have blue cheese in the house I'd often eat some just before bedtime to make the night a bit more interesting. It doesn't make them happier or scarier, just more vivid and with more complex plot lines
If you want some exciting dreams you could try taking Valerian root extract.
I've woken up traumatized and appalled at myself for dreaming the sort of stuff I came up with on Valerian.