Over-Crowded Buses/Trains and Spare Capacity

There has been quite some complaints about buses and trains being too crowded ever after all the taxi companies in Singapore raised their fares. However, the bus companies & train companies claim they still have quite a lot of spare capacity with the current load.

Why is there a difference in what people feel and what the transportation companies claim then? I did a simple calculation the other day while taking a bus. That bus was said to be over-crowded by my colleague, but I looked at the loading capacity. For a double-decker bus, the lower deck has a standing capacity of 41 persons. On that day, there were only about 30 persons standing, yet we already felt a bit squeezed. If we want to fill to the full capacity of 41 persons, we will have to pack like sardin fish. That is the difference. Comparing our trains with those in Japan, probably our trains are not really that crowded or jam-packed, yet.