INteraxe,
your german is probably better than mine, but isn’t mir an amalgamation of dative and ablative?
<?xml version="1.0"?>
Perhaps the different categories of the dative seemed more or less like one and the same to a Roman. While the grammar books may give a grocery list of different usages, the Roman probably had a general sense by which he basically seemed to be using the dative almost the same way every time he used it.
The best way to learn and internalize Latin idiom is through prose composition. Buy a copy of Bradley’s Arnold Latin Prose Composition and, in spite of the drudgery of some of the passages, keep working through it. Gradually the language and constructions will feel more natural to you.