system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are people tempted to pick their scabs when all it will do is bleed, hurt and scar?
gpt
scabs are more rigid than the surrounding tissue. in the course of normal movements this causes the scab to irritate the skin nearby. scratching aleviates that sensation.

additionally, scabs dont have nerves. picking at them stimulates the nerves underneath which removes the alien sensation of a "dead" spot where the scab is. 
if you've ever had some part of your body numbed, you'll find yourself poking at it for much the same reason. much to the chagrin to dentists everywhere.