Can’t remember last night’s make-believe adventure? Don’t skip step four.

Whether you’re in the middle of a deep slumber or tossing and turning in the early hours of the morning, a vivid dream can be a highlight of your sleep routine that you never expected. But as wild as dreams can be—fantastic adventures, terrifying nightmares or really strange mysteries—they’re notoriously hard to remember when you wake up. If you’ve ever wondered why you can remember dreams that feel unremarkable and not others, you’re not alone.

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“We remember dreams when we wake up during a dream for long enough to think about it for at least a few seconds,” explains Jade Wu, Ph.D., a clinical psychologist in the department of psychiatry and behavioral sciences at Duke University. “Often, we dream, wake up very briefly, and that dream is gone forever because we never encode the memory of it into long-term memory.”

Remembering the details and scenarios of more pleasant dreams, however, is extremely challenging for a vast majority of humans, Robbins says. Unless it’s a recurring dream, you’ll need to remind yourself to take a few conscious steps to cement some details in your mind’s eye before the dream slips away.

“Alcohol, drugs and sleep deprivation may lead to worse sleep quality in general and may also lead to nightmares,” says Wu. “Wildly inconsistent sleep-wake timing can also throw off REM and disrupt dreams.”