What are the bad sections of Chicago?

It depends what you mean by bad. Locals are the people who live in all neighborhoods, so it really depends on your perspective here. People on the north side think the entire rest of the city is bad. Most of the north side is safe, although from Uptown & north along the lake has a few issues. On the south side, Woodlawn, Englewood, and Grand Crossing probably have the biggest crime and gang problems. North and south of those neighborhoods doesn't look fancy, but it's not "bad." The west side has the largest problems with crime and gangs - Lawndale, Garfield Park, western Humboldt Park and Austin are probably the worst areas of the city.