In my feedback for URA’s Concept Plan 2011, I followed up on the suggestions of the focus group to improve walkability. From comparing my own experiences walking in Singapore versus elsewhere, I found that I enjoyed walking much more in cities with frequent intersections. It means you don’t have to walk a long way to the next intersection if you want to cross a road, and it also slows down traffic, thus increasing the pleasantness of the environment for walkers. Apparently there’s now a study supporting my intuition.
In terms of friendliness to cyclists, too high an intersection density might prove annoying unless there is a “green wave”. But too low a density, as is the case in Singapore, means that the few intersections there are tend to be large and high traffic. These tend to be more dangerous for cyclists. The parts of my Singapore commute I dreaded most were the tricky intersections. After many hours of staring at maps I was still unable to purge them from my commute, and any commute from the northeast to the west of Singapore remains woefully unconnected by any park connectors.
One Less Car 
I would say several roads that are entrances or exits to highways are quite bad as well, for example, Lentor Ave/SLE http://bit.ly/czZHmA and the Upper Changi Road East/PIE/TPE http://bit.ly/bY5Vf9
The cars are very fast, you have to be on the second lane to cycle “safely” across, but cars, those who want to enter the expressway at the last minute, will often horn, follow closely, almost to a point of side swiping you, even though you’ve given them the lane on the left hand side of the road.
Oh, and there’s no easy way to get from North to the East side either.
Yup, I had the same problems at the filters along Braddell Road into Toa Payoh, and the PIE filters on Lornie Road.