I have just began the lesson to imperative tense.
Wouldn't it be fine as well to tell when to use imperative.
Now that I live in the country and learn also the language in real life, everybody have said me that imperative is rarely use.
And as I live here, I feel your sentences indeed a bit rude ! (what an impregnation of danish culture and lifestyle !)
The reason, I think, that we don't use imperative as much as in English, is that we don't have the word 'please' in Danish. In English 'Read this' would be a little rude, but then you can add 'Read this, please'. In Danish 'Læs dette' would be rude in the same degree as in English, but because we don't have please, we often rephrase the whole sentence to 'Gider du læse dette' (Do you want to read this) or 'Vil du være så sød at læse dette' (Will you be so kind as to read this') and thereby the Imperative tense is gone.
Imperative is still used quite often, I would say, e.g. in exclamations (Se dig for, Pas på etc.) or as commands between parents and children (Opfør dig ordenligt) or between teachers and pupils (Sid stille), and in standard phrases (vær så venlig at..., hav det godt, Hils dehjemme)