Machiavelli

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 would profit by the old order, only lukewarm defenders in all those who would profit by the new.
Machiavelli - The Prince
Men are so stupid and concerned with their present needs, they will always let themselves be deceived.

It must be remembered that there is nothing more difficult to plan, more doubtful of success, nor more dangerous to manage, than the creation of a new system. For the initiator has the enmity of all who would profit by the preservation of the old institutions and merely lukewarm defenders in those who would gain by the new ones.

- Machiavelli