It happens quite often that new posters are confused about the scope of this site, for instance mistaking it for a "you can ask about every possible study topic here" site, or a "here's the story of my life, what should I do" site. This leads to off-topic questions, additional moderation work, and unnecessary hard feelings from newcomers.
On SE sites it is possible to customize the content of the "how to ask" window that is shown to first-time askers. See below for how it looks like on Academia (non-personalized) and Server Fault (personalized).
Here is how it looks like on Mathematics, where it is even more informative (or at least it did at some point in time --- I don't want to create a new account there just to verify that this screenshot from the Meta.MO question is still accurate)
I suggest to add some text to describe the scope of our site; for instance, a shorter version of the "What topics should I avoid?" paragraph on the help pages.
Similar thread on Meta.Mathoverflow (where unfortunately the suggestion was never applied).