A practical attitude
We were having a repetition class a few days before a test. I had prepared a worksheet with a set of tasks similar to those planned for the test. One of them was drawing conclusions about the past using modals (can't have, must have and so on). Among others, I prepared a cue “He was rich and handsome, but she didn't want to marry him.” I was expecting something like “She must have been in love with another man” or “She can't have loved him.” What I got instead, and quite promptly, from a very gentle and sweet 18-year-old girl was “She can't have been normal!”