I've cycled in Sofia, Bulgaria. For a long time i was too scared to do it as the roads were full of huge potholes and the general standard of driving seemed to be appalling. Dangerous habits like extreme speeding, tailgating, jumping red lights at high speed, etc. are commonplace.
The city repaired a lot of roads a year ago, so I took the plunge, ensuring I had a helmet and hi-viz waistcoat, not usual attire for most Bulgarian cyclists who just cycle in whatever they're wearing. I found most drivers gave me a wide berth: maybe they thought I was a police officer.
In the end it was not the cars, lorries and buses that were the problem at all. Rather more terrifying were the packs of stray dogs that I would encounter occasionally on quiet side streets. Also there is a particularly large, vicious type of guard dog over there: these dogs appear unencumbered by any type of restraint and I was chased several times.
So the usual rules about cycling that we observe in this country (stick to quiet streets, avoid busy roads) were reversed. To avoid the canine menace, I had to mix it with traffic on the fast roads. Recommended only for reasonably confident cyclists...
Oh yeah, there are some nice and really helpful little bike shops in the city. Very quick and cheap maintenance if needed.