Rosh Hashana falls in the month of Tishrei. The letters in the word Tishrei go backwards counting from the end of hebrew alphabet. In english that would be like ZYXE. In contrast, Aviv, the word for spring, is starts with Aleph Bais, like ABIB if it were english. So why are the months named this way? Or why wasn't the spring month, Nissan, the first month of the year? In fact, the first of Nissan is a new year, as the Mishnah in Tractate Rosh Hashana states (there are four days that are called "new years day" for various reasons. But the main New Year for Jews is Rosh Hashana. In order to really have a new year, it is important to let go of the past. By counting backwards, like the word Tishrei does, we can see where we can imporve ourselves.