Firstly I think the most important thing in engineering is nothing is free. If you change a parameter in your design something else has got to give. If you increase the cargo capacity of a plane it is probably going to have a slower cruising speed. The hard part is finding the sweet spot that exactly fits the requirements of the client or use case. And also! now a dosen of other parameters have shifted to, like weight balance or climbing rate. How do these fit in?

Now for software, let's say you have two clients with almost identical requirements for a piece of Software. The only difference being one of them thinks time to market is important, the other one has less focus on time. As a software engineer you should produce two very different pieces of Software for these clients. You will have to make decisions based on the time it will take to implement something and also understand the effects of this on other aspects of the end product.