Even more than the original series, The Next Generation was well-known for diving into the murky waters of ethics and philosophy—and in the process, demonstrating how a sometimes silly space show could make profound statements about the meaning of life.
For example, check out season six's "Tapestry." The episode starts with Picard getting his space-pacemaker blown up, stopping his heart. He dies and goes to the afterlife, where Q shows up. (Worst Heaven ever.) Q gives Picard the chance to go back in time and undo the fight from his early 20s that messed up his heart in the first place—but when he does, Q shows Picard what his life would have looked like if he hadn't gotten into the fight. Instead of the awesome starship captain we know and love, he would have ended up being just some low-ranking schlub on the Enterprise. The moral of the story? Our mistakes make us who we are, and the best part of life is taking risks, even if it means being beaten up in the process.
Another example is the series finale, during which Picard realizes that after all his years of space exploration, his real adventure was one of self-discovery. Visiting far-flung corners of the galaxy is great, but learning more about ourselves—our strengths, weakness, limits, and deepest-held beliefs—can be even more valuable in the long run. Even if we don't get to hop around the galaxy on the Enterprise, we can still be explorers just like Picard. Thanks, Star Trek!