If you don't want to take the taxi, that's okay, rent a bike and pedal to your destination. The city has public bikes spread all over the city with many bike lanes and trails to take. Don't want to take a bike either, that's okay, you can walk. Seoul is such a walkable city. Sidewalks are everywhere. There are many pedestrian overpasses and underpasses spread all throughout the city, so you don't have to worry about walking right next to traffic.
Even though Seoul is a big city, you can still get your fill of nature. Seoul has many green and natural spaces. Large parks like the Seoul Grand Park, Hangang Park, and Seoul Forest are large parks people typically go to for recreation and relaxation. The city also actively works to preserve natural ecosystems through projects like designing protected areas for wildlife and creating small habitats for them.
One of my favorite aspects of this city is the safety. Seoul consistently ranks as one of the safest cities in the world, with low crime rates and resources for public safety. I feel safe even walking around at night. This is a feeling I'll miss when traveling to other countries and going back to the US.
People living in Seoul face challenges such as the high cost of living, overcrowding leading to a lack of personal space, and air pollution. In addition, the work culture in Seoul is very competitive and stressful. The pressure starts with excelling in your studies when you are a kid. Kids are expected to go to after-school academies after school.