Its always hard for me to decide the opening line for a paper. Here’s an opening line I ran across recently in a statistics paper.
Imagine we own a factory that produces nuts and bolts.
You had me at hello!
Here’s another great line, taken from the preface to the third edition of Theory of Probability by Harold Jeffreys.
Some points in later chapters have been transferred to the first, in the hope that fewer critics will be mislead into inferring what is not in the book from not finding it in the first chapter.