Well, I don't say that all taxi drivers in Singapore are rude. However, I would say that about 60%-70% of those rude motorists I usually find on Singapore roads are taxi drivers. What I mean by rude here is that they have lack of consideration to other motorists while driving.
Some of such inconsiderate driving acts include reckless driving, sudden stop to pick up or drop off passengers, and cutting other car's lanes. They also tend to drive above the maximum speed limit on all types of road, be it expressways or normal roads. They always want to get to their destinations at the soonest time possible, since it seems that every second wasted on the roads means lesser income for them... not too sure whether it's true or not, perhaps anyone can clarify? :)
One example of such inconsiderate acts: On 14th of July 2006, about a week ago, at around 9:30am in the morning, I was driving to my office at Science Park. Along South Buona Vista Road, just after the Buona Vista flyover and before the junction to Science Park Drive, the first and second lane from the left are merging into one. As you might have known, the rule for merging line in Singapore is that cars on each line have the right of way on a round-robin fashion.
My car was on the second lane from the left, and on the most left lane, there was another car and a TransCab taxi tailgating it. Based on the current position of all the three vehicles, whereby my car is in between the two vehicle even though it's on the other merging lane, I should have the right of way right after the other car, before the taxi. But guess what... the taxi kept on tailgating the car in front of it, and the driver never had any intention to give way even though I had the right of way at that time. So no choice, I had to slow down and give way, since I don't want to risk my car to be involved in an accident. No wonder why most of all accidents in Singapore usually involves taxis...
That's not the only incident I have experienced involving taxi drivers while driving here. Well, I really hope that the taxi companies will be more selective in hiring their drivers.