Buses are the unrecognized champions of public transport in modern cities around the world. However, the bus system is usually bedevilled by poor design that has resulted from poor understanding of how a bus system actually works. This article examines the impacts of the interactions between buses, passengers and traffic on delays and capacity at bus stops. First, issues like the stages of bus stop operations, causes of delays, and the interaction between bus frequency and stop delays are analysed. This suggests the necessity of microscopic simulation to study stops operations. An illustration of the sort of understanding that can be achieved by means of simulation experiments regarding arrival patterns of buses and passengers, boarding times, difficulties for leaving the stop and vehicle capacity is shown. Results indicate that it is important not to underestimate the real situation found at bus stops, as designing for ideal conditions will be insufficient if the reality is different. Application of these results shows that dramatic improvements can be made to the performance of the bus system as a result of a better understanding of its operation leading to simple changes in the design of infrastructure.