The Boston region has some of the world’s worst traffic. It is also one of the world’s most walkable urban areas, and it’s an increasingly popular region for commuting via bike.

Throw that all together. Then add a particularly light-bending population density and a topography born of infills and inlets. And you’ve got some of the most stressful driving, biking, and walking conditions under the hot, hot sun.

That stress can make drivers, bikers, and pedestrians do things, can’t it? Things they shouldn’t do perhaps? It also leads to a lot of finger-pointing, never mind to some truly horrific results.

And that leads us to our latest open thread. Which is the absolute worst in Boston in terms of hassling others and just generally causing headaches: Pedestrians, bicyclists, or drivers? Sound off in the comments section below.

• Boston one of the world’s 20 most congested cities [Curbed Boston]
• Boston walks: 10 perfect ones for warmer weather [Curbed Boston]
• Boston’s 10 most bikable neighborhoods, explained [Curbed Boston]
• Should you move to Boston? [Curbed Boston]
• Boston reclamation: The 5 most significant infills in the city’s history [Curbed Boston]
• Cambridge bikers form human barrier during rally for protected bike lanes [Curbed Boston]