If I understand well the difference between your two end-sentences one of them is more like an order. There is just a little border line in the meaning, one is a kind remark while the other is perhaps more direct.
But I believe it is clear for me now.
Thanks to have a patience to read me and to correct me (For me defense I can just tell you it's not always easy to perceive all the subtlety of English language).;-)
I do believe that French has just has many subtleties! In any case, thank you for bringing up these two sentences and my thanks go to Barb D. for pointing out the subtle difference. In practice, of course, it is more important just what tone you take with your voice and your facial expression. Depending on how you say it, either sentence could get across your meaning -- whether to order, to remind, or just to nudge someone a little.
In other words, the subtlety may will be more in the style of delivery than in the words. Again, I imagine that is true in French, as well, no?