It must be considered that there is nothing more difficult to carry out, nor more doubtful of success, nor more dangerous to handle, than to initiate a new order of things. For the reformer has enemies in all those who could profit by the old order, and only lukewarm defenders in all those who could profit by the new order. This lukewarmness arises partly from fear of their adversaries, who have the laws in their favour, and partly from the incredulity of mankind, who do not truly believe in anything new until they have an actual experience of it.
Niccola Machiavelli, The Prince
The above was written 400 years ago. It seems just as relevant today as it was back then. Below are some other interesting quotes.
Generally speaking, the younger and more highly educated people are, the more likely they are to change
Resistance is often a reaction to the methods of instituting change rather than change itself.
Many people fear the unknown and the uncertainty accompanying change. They also fear losing their jobs, losing respect or status and failure.
When logic vies with emotion it rarely stands a chance.
Romney & Steinbart