The first 100 days sets the tone for the administration. We learn genuine policy goals, the manner in which the President will interact with legislators, foreign leaders, the public, the media, and critics.
We learn the communication style of the White House, as well whether the President intends to strong-arm his or her agenda via executive order or work with legislators to pass bills through Congress.
The level of compromise the opposing party can expect becomes evident during those first 100 days, as well. This is really a reliable test of a President’s strength, character, and leadership abilities.