Why are so many people ashamed of riding the bus or walking?

[mira]

If it takes you half an hour extra each way to get to work that's 20 hours a month. Not everybody has an extra 20 hours a month to spare for transportation. Mira and CatsNK, I can see your point if it's an extra 10-15 minutes, but that's not the case for a lot of people.

That's understandable. There are a lot of variables.
If I had a car, I'd have to drive the same route as the bus and would probably end up getting stuck behind it in traffic anyway, so it's a kind of stalemate situation.