When you learn a new language, particularly as an adult, you learn that you have limitations in its use and to be able to accept and work around them. You learn that that's nothing to be ashamed of, because you put in a hell of a lot of work and can now function in what used to sound like complete nonsense to you. You learn to prioritize keeping things short and simple to minimize the chance of your being miss understood.
In your native language, amongst native speakers, everyone's so skillful at communication that there's often more of a focus on how something is said than what is said. I.e. it's so clear that other speakers will understand a speaker's basic "I want to have this done by tomorrow" message - however they formulate it - that they often put more focus on other issues, such adding jokes or word-play, ensuring the correct level of politeness is used or communicating the nuisances of their current emotional situation. To other native speakers, that results in a richer signal, one containing more information which costs them no effort to understand and which they can filter out or pay attention to as they wish. To a non-native speaker, that additional information is just noise: like listening to a message over a bad radio signal. It costs them a lot of effort to attempt to understand it, they often fail in doing so and it gets in the way of their comprehendig the core message. They just want to hear "I need it by tomorrow morning", not "If it isn't too much trouble, is there any chance we could get this done by tomorrow?"
A monolingual can get this in the abstract, but it's easy for them to forget. Someone who's gone through the millions of minor embarrassments, humiliations and triumphs it takes to master a second language is far better disposed to remember it and act on it in practice.