One moment you’re happily stranded on a desert island with a buxom blonde; the next you’re being chased by an angry mob of Peter Lorre look-alikes wielding hideously large Vienna sausages. No wonder you wake up in the morning and think, What was that all about? Though the meanings of dreams largely vary with personal experience, the interpretations of certain symbols are universal. “Symbols in dreams are like symbols in literature and mythology,” explains Dr. Morton J. Aronson, professor of psychiatry at Columbia University. “They are fixed characteristics of the human mind.” Here are six of the most common themes, decoded for your convenience.

Caves
Anything that can be entered, including tunnels, doorways, bureau drawers, and especially mossy little caves, represents—duh—female genitalia. Your unconscious is trying to tell you what your buddies have been saying all along: You need more action, and not the kind you get from watching Jackie Chan.

Running
If you’re being chased, you’re running away from something that is unconquerable or avoiding a confrontation. It’s time to tell your girlfriend that if the Kajagoogoo records have to go, she has to go, too.

Aliens
Dreaming of little green non-Irishmen means either you fell asleep during The X-Files again or you’re feeling a little unsure of your surroundings. It can also be an indication that some outside force is invading your life. If the aliens are accompanied by memory loss and chronic rectal pain, however, you should really consult a physician.

Water
A calm stretch of water stands for the original wading pool, the maternal womb, and signifies safety and comfort (you lucky bastard). Turbulent water, on the other hand, can mean there’s a disruptive force in your environment or that you feel overwhelmed. Buying into fewer pyramid schemes and dating sane women should clear this right up.

Falling
A Wile E. Coyote–style drop off a cliff generally denotes instability in your life, but a free fall with no clear beginning or end represents a lack of connection to the world around you. It also means you should consider installing guardrails on your bunk bed.

Persistent nightmare in which you brutally murder all your coworkers
Don’t worry: You’re a sane and well-adjusted individual. Now get back to sorting the mail.