Thinking you are perfectly normal all the time is not always a good thing.  You can create havoc around you all the time.  You have no realization of your faults.

For one thing normality is a myth.  No one is perfectly normal.  Every one is imperfect.  Every one is a snowflake.  God never created the same person twice.

You really need to be aware how you come across to others–your idiosyncrasies, then you can compensate for your behavior around others.

If you think you are perfectly normal, you can discount your behavior towards others and have no idea the damage you can causing (???) towards others.

Wasn’t it Socrates that said many eons ago “Know yourself”?  The better you know yourself (???) you, the better you can judge the impact you are having on others.  And change accordingly.