For example, digging fossils, you can just do it one day, but you actually have to do it many times to collect one set. Then there's flowers - you want to keep watering the flowers every day, and people that are interested in taking care of the flowers, can water the flowers, and make different, unique types of flowers by doing so every day. By doing those things every day, you can achieve something bigger, and you can also get a sense of satisfaction from it. By doing those everyday things over and over, it will deepen your experience in this game, creating a deeper, more meaningful life in the town.