hi S., my son tried that word out too, around the same age. i think they all do. at first i was so shocked and upset i reacted harshly, i couldnt help it. after another 1 or 2 times, i realized he couldnt truly understand what the word means. so i sat down with him and gently asked him if he knew what it means, he didnt really. i told him it means that he doesnt love me. well, he looked like i punched him, and he started to cry, he was so upset. he said its not true, he does love me. i said i know, i love him too, always will, and then we talked about how you can be upset with someone even if you love them and other words we can use or other things we can do. he never said it again, not to me, anyway. its not all hallmark though, i heard him say it under his breath about his sister a few times after that, i always corrected him, and always reiterate that we dont use that word, we might be angry but we dont hate. he doesnt say it anymore, hasnt for a long time. and i am more careful about using the word myself. he corrects me! "mama, we dont say hate!"