I guess you mean the 2nd person form (du or ihr fir singular or plural) instead of the 3rd person plural (Sie), which is the courtesy form fir singular and plural.
Yes, in German it’s a big deal, roughly the same as saying “Hey dude” instead of “Good morning Mr Smith”.
Yes, in German it’s a big deal, roughly the same as saying “Hey dude” instead of “Good morning Mr Smith”.