Engineers do not like surprise. We prefer to know the result ahead of time with reasonably good estimation. We are well aware of the Murphy’s Law, so we will leave some safety margin to cope with the uncertainty. However, we will still do our best trying to to minimize the uncertainty.
On the other hand, girls seem to like surprise alot. They think surprise is romantic and shows much their boyfriends care about them. In fact, this is actually based on a wrong perception. Having an execution well according to the plan with lots of check and balance demands more effort than having a surprise. Since surprise usually lacks feedbacks and inputs from the customer (i.e. the girl) in the planning process, the quality of the end product suffers. When the girls receive a surprise, they are just too overwhelm by the element of surprise so they simply overlook other problems. In fact, the total amount of pleasure experienced by the girls is much more in a well planned execution than in a surprise. Those pleasant experience just goes unnoticeable because it is distributed over the course of the planning period.
Sometimes, the girl may be unhappy about the surprise delivered because it doesn’t match her expectation. The problem is that if the girl refuse to give inputs during the process, there is simply no way to guarantee a satisfying end result. The feedback loop is broken. Just like the product design engineers can’t build a product satisfy the customer’s requirements if the marketing department gives us confusing or insufficient specification. Surprise and quality is mutually exclusive, you can just pick one. Actually, you can attempt to balance quality and surprise. The important parts have to plan carefully, then randomize some trivial parts to add some surprise for decoration.