Ofcource excess of money is harmful. Because you gradually forget about the value of the money and start spending lavishly knowingly or unknowingly. I personally think everyone should have money for their basic needs and for safety purpose. When they start spending on luxury things which is really not useful then it is time for them to help others who really need money but practically speaking all wont start helping others once they feel they are financially sound.
There are only few good hearted people who helps others once they get more of something. Money is something people wants more and more but never gets satisfied with that grafually money makes human runs after it and makes him to do anything and everything for it.