I came across a question in an English practice workbook like this:
I'm exhausted because I've worked/I've been working in a restaurant for the past three weeks. I've never realized/I never realized before how hard the work is!
Upon checking the answers, the first one is I've been working (present perfect continuous),which makes sense, but the second one is past simple (I never realized). It doesn't make sense. From what I've learned, "never" is typically used with the present perfect or present simple as an adverb of frequency. In what case can we use "never" with the simple past? Is this for emphasis, or is there some other advanced rule that I've never heard of?