In regards to Trumps behavior "I think" it is because he is battling too many fronts. Tremendous amount of personal attacks on one side and world and national issues on the other. If the incessant viciousness of the personal attacks ( not only from Democrats) would be cut in half, I am sure you would see a more pleasant President concentrating on other more pressing issues. He is a human being and still subject to feelings and people should stop (reduce?) the attacks and let him do his job. 
If you were being called out loud an 'AH' every day at work and knew elements were out plotting to eliminate your presence by co-workers and others, how would you react? Would you be able to concentrate on your duties effectively? True Americans demonstrate support for their country and elected leaders and work for changes in more positive, civil ways versus direct, vicious confrontations which only elicit a defensive and negative response benefiting no one.