Everyone has probably had the experience of working with colleagues who complain a lot. People usually complain out of frustration. Left unchecked, prolonged frustration can lead to depression. This is why it is important to tackle the root source of frustration. In the workplace, frustration can build up in large organisations due to red tape, inter-department politics, communication breakdown, lack of mentorship. This can ruin the experience of the day. There are people out there who have mood swings and hanging around such people can surely bring your day down as well. Immature people handle frustration by complaining. This is why it is important for a mature person to guide the immature through times of frustration. Framing the problem as a learning experience is a good way to move forward on frustrating issues arising in the workplace.
Working with a deadly combination of tight inflexible deadlines and pushy people is surely a recipe for frustration. Most people simply cannot thrive in such harsh circumstances. Rather it is recommended to find jobs that allow greater flexibility and freedom to make choices. To avoid frustration, always work within your limits. Know when to take a step back to gain perspective on the issue or bottleneck.