Making your living area overly sterile
As with above, a little bit of direct, bacteria, grime, whatever you choose to call it, is actually beneficial in the long run to your overall health. Everything can be good in moderation, and bacteria is no exception. Excessively sterile environments to germs mean the immune system can’t learn to cope with exposure to bacterial threats, and so when removed from that sterile environment the risk of getting ill or developing a chronic affliction is increased. Hygiene is a fine balance between these levels.
