Hundreds of years of slavery and persecution come to a climax where God himself takes us out of Egypt. However, before the actual Exodus, we find something puzzling. HaShem told Moshe that he would be the one to take Klal Yisrael out of Egypt. He gave Moshe certain signs so that when he would approach the Jews, they would realize that he was telling the truth about himself.
At first, Moshe was received warmly. The Jews were ecstatic! Finally, it’s over, this suffering is over! However, when Moshe approached Pharaoh, he wasn't met with the same excitement. Instead of sending out the Jews, Pharaoh increased their suffering. He forced them to make the same amount of bricks, but he withheld the necessary ingredients to make them. Instead of the redemption that all the Jews were waiting for, they were met with greater suffering.
Why did this happen? God could have brought the plagues right away without increasing their suffering! He could have begun the redemption without making their lives even more miserable! So why would he set up the redemption in a way where they experienced even greater suffering first?
I think the answer could be explained with a parable. A very wealthy individual won a raffle which allowed him to spend a night in the nicest luxury suite in the most expensive hotel in town. It was nice for this man to spend his little vacation, but since he was so wealthy he had already frequented this particular hotel numerous times. He enjoyed his stay, but afterwards he didn't think much of it. The next week, however, a poor beggar won the same raffle. In contrast to the wealthy man, when he showed up to the hotel he couldn't believe his eyes! Such magnificence and grandeur! To that poor beggar, that night was one he would remember and cherish for the rest of his life.
The same basic psychology is true with us. Although the Jews didn't understand why their torment was increasing, it was specifically because their pain increased that they were able to experience and enjoy the redemption in a way which would last millennia. Until this day we remember the Exodus every morning when we wake up and every night before we go to sleep. It’s become a part of us, a deeply embedded niche in our Jewish conscience. But it only became that way because we knew how hard the other side felt. We knew what suffering felt like. We knew what it meant to be a real slave. So when we finally experienced the Redemption, the memory stuck and will remain with us until the end of days. The suffering of slavery and persecution forced Klal Yisrael to have a deep and unshakable appreciation for the freedom of redemption.