The Medresh (Mechilta, Yitro 19) states: "All beginnings are hard.'' However, what's the reasoning for that? The natural tendency is to start the year off strong. Why do chazal tell us that every time we start something new that we are going to have a hard time?
Rabbi Yochanan Zweig explains that whenever someone starts something new they automatically look towards the future and are forced to make a long term commitment. For this reason, Rabbi Zweig explains, the Medresh states "all beginnings are hard"--as it is at the beginning in which one needs to make a commitment to stay dedicated for the long run.
Similarly, Rabbi Zweig explains that the torah (Devarim, 11;12) states: "From the beginning of the year to the year's end." Rashi (11;12) explains that the torah is teaching us that "from Rosh Hashana it is judged regarding what will be at the year's end." We see from here that when the torah speaks about Rosh Hashana it focuses on the end of the year--as whenever one starts something they naturally focus on how it will be in the end.