What you say rings true. I'm not much of a THC user. Maybe once every couple months. When I do, I sometimes have very wild dreams early in the night, but I'm less likely to remember them. I don't use it much before bed, because although it feels as if I slept soundly, it always makes me wake up tired. I'm much more familiar with alcohol, and my sleep is divided by it each night into two parts. The first four hours of sleep are usually dreamless. At almost exactly four hours, I wake up and drink water. The next 3-4 hours are where the dreams occur. If I'm really catching up and can stay in bed for a full 9-10 hour sleep, the extra hours contain the most vivid, hallucinogenic dreams. So in my experience, I think both those substances impede good dreaming.

I don't mind nightmares. I kind of like them. Even if they're horrific I end up recalling them to help myself get back to sleep; then usually the ending changes.

Yes. Well, sometimes I drink wine or beer. I do my best thinking when the caffeine is at a maximum, my mind is racing, and the first 1-2 drinks are starting to lower my blood pressure and calm me down. Does that seem unusual to you?