Hair cuticles are very small tiny scales which are invisible to human eyes on our hair. These scales like feather are organized in one direction on our head. They play an important role in retaining moisture in our hair. When we bleach our hair, we open these cuticles using chemicals and then bleach the hair. When we condition our hair, we smooth out the cuticles so the hair becomes soft and shiny.
The cuticles are always aligned in a similar dimension when it remains on our head. However, when we take the hair away from our head until we maintain the direction of the hair by tying it properly at the roots, chances are that we may end up mixing the hair directions. Once the hair direction is mixed, it can cause hair tangling because all the cuticles tangle with each other. That hair is called Non-Remy.