You feel nervous when you have to do something that involves some risk: things may go wrong1. For example, when you have to give an important presentation, when you approach a person whom you would like to get introduced to, or when you have to take a driving test. Nervousness is inherently linked to doing things – if you are passively waiting for something to happen, you won’t feel nervous, but rather something like anxiety or worry. You can also be nervous about something potentially positive. Most other fear-emotions are about the possibility of losing something you already have. You can also be nervous, on the other hand, about the possibility to not attain something, such as a medal (for your performance in a sports match), a position (for your performance in a job interview), or the respect of your peers (for your performance giving a presentation). In nervousness, you contemplate the probability of succeeding in the thing that you want. The word ‘probability’ implies another important aspect of nervousness: the situation is not entirely under your control. Even in a situation in which you are technically in control, like when giving a presentation, you can still be nervous because you think that you may get a blackout, or that you may run out of time before you finish.
Time in general is a very common elicitor of nervousness; specifically, having too little time to do something. Walking to get the bus may otherwise be a relaxing affair, but when the bus is about to leave, it can become a nervous activity.
In the comic, Murphy gets very nervous when he learns that the whole department is already waiting on him for his presentation, for which he thought he still had time to prepare. It is made worse when he learns that senior management is also present.