It depends on the city. I'm used to urban riding so I'm not predisposed to avoiding cities on my bike. I love to bike in some cities including Paris, San Francisco, Seattle, & DC. One city which I really hated for biking (but which otherwise liked) was Bangkok, due to the dense traffic, heat, & humidity. Chiang Mai, Thailand was unusual because I found that I enjoyed biking within the city, but getting in and out of the city was not pleasant due to heavy traffic and the lack of shoulders. San Jose, Costa Rica, has chaotic traffic, so not my favorite place for biking despite great weather. Medellin was a mixed bag. Some parts of the city are extremely hilly. Smaller roads in flat parts of town were OK, but busier roads and roundabouts were not fun.