Why do I have bad dreams?

It’s my personal opinion that my life is quite good, but my dreams tell me a different story. They’re generally bad, stressful, wake me up and to often leave me quite depressed. What gives? Well, we all know that the question of whether dreams have meaning has been pondered by philosophers and scientists for centuries, and there's no one definitive answer.

So, I take it that dreams are a random form of mental housekeeping that follow neither rhyme or reason. In other words, a wide variety of disassociated and disjointed components are thrown up in the air and fall wherever they feel like, often making me feel pretty bad for no good reason, and unfortunately wake me up several times in the early hours which I don’t appreciate at all. 

Add to that their depressing tone and negative message that force me to fully wake up and tell my brain that it is pure BS and I should ignore it, as I order the rest of my body systems to return to sleep. And that is, at this point, when I often get no satisfaction. I can’t get back to sleep. I’m not happy, but this is no serious matter, it’s just become a dreaded routine that I will survive well!