We go to Church services on Saturday because it is the true Sabbath day. God ordained the seventh-day (Saturday) a holy day after He re-created the earth (Genesis 2:3). He commands His people to observe this day in the Fourth Commandment—and, contrary to what most people say, the Ten Commandments are still binding on Christians. In contrast, God never ordained Sunday a holy day—and none of the Ten Commandments reference Sunday as being special in any way.
In addition, Jesus declared that the Sabbath was made for man (Mark 2:27). This means that God created the Sabbath as a day to be enjoyed by all of mankind. Although most people think otherwise, the Sabbath is not a burden. It is actually a day to look forward to each week—a guaranteed day of rest and rejuvenation.