Picking your nose and eating it may be beneficial to your immune system.
A study done by Stefan Gates stated that 44% of adults admitted to picking their nose and eating the dried mucus.
The even grosser part was they said they liked it. Gates comments that "our body has been built to consume snot," because the nasal mucus is normally swallowed after being moved inside by the motion of the cilia Mucus filters airborne contaminants.
Eating it helps our immune system become stronger and learn to fight off all those contaminants. We swallow a lot of our mucus anyways through the nasal passage down the throat.