Yeah apart from more traffic on the single tower, towers handle more traffic by reducing the output power, so they basically shrink in range to increase throughput. In some cases, you might loose connection completely because you fall out of range if there are a lot of people using the same tower at the same time. Depending on your location, towers might be laid out in a way that in the worst case, gives you a blind spot (some operators will actually balance this into their costs when laying out towers vs chances that this happens, while other places will give a perfect overlap in towers for any situation). This is noticeable in some situations like rush hour traffic, where you are in the middle of a call, and your call drops suddenly because the towers no longer overlap due to increased network traffic. If that happens, your operator was thinking about costs and not service quality 