Overthinking of a particular irrational fear that one has can turn into an anxiety disorder called a phobia. Affected people in order to avoid their fears and situations can go to any bizzare extent. If they are unable to overcome their situation at an early stage, then it turns into different types of reactions like sweating, trembling, heavy breathing etc. Phobias are different from our regular petty fears. Phobias are merely irrational fears as there is no logical base of that fear but people experiencing phobias become mentally and physically very distressed depending on the level of phobia. 

1. Optophobia: The fear of opening eyes. Just imagine what the person who has this phobia must be going through. People affected by this phobia prefer to stay in dim lighting. This phobia can be a result of past experiences.
2. Hynophobia: The fear of sleep. In this phobia people are scared of closing their eyes and sleeping. Just the thought of sleep induces anxiety and stress in the affected person. It's well proven that we humans need sleep to function properly as lack of proper amount of sleep can result in shifted focus and instability. A person suffering from this phobia will not be able to function properly. It's not that hynophobics don't feel sleepy at all but the sleep that they do get is far from being a restful sleep that a normal human beings requires. Experts say conditions like insomnia, sleep paralysis and night mares contributes to the development of this phobia. 
3. Allodoxaphobia : The fear of opinions. This phobia is related to social phobia in which a individual is scared of the opinions and judgements of other people. They start panicking because of other people forming judgements about them. This fear primarily develops in early life stages because of any traumatic incident. Such people mostly keep themselves isolated and completely avoid participating in social activities.
4. Oikophobia: The fear of home. people who have this phobia are scared of staying at their house. Weird isn't it as for majority people, home is a safe space and after reaching there the whole day's exhaustion goes away. The sufferers of this does not belief in the saying that “ home sweet home” because everything related to home including taking a bath, using electrical appliances induces fear in it's victim of death.
5. Ablutophobia: The fear of bathing. Individuals affected from ablutophobia feel anxious and fearful when it comes to bathing washing or cleaning. This phobia can be because of a past experiences and it is also related to genetics.