One of my acquaintances said something blasphemous regarding Hazrat Izrael (naudubi Allah). He said that while pointing to his parents. He said "there are Izraels (he referred his parents) in our house" (naudubillah). Everyone present there laughed at this and as a human nature a little laughter also came down my face but i immediately stopped when I realized it was not good. I controlled myself. The same happened today someone said something that can be included in kufr and as a human my nafs again pushed me to smile at it but immediately I controlled my smile. What should I do? How do I avoid it? It is obvious that you ultimately laugh being a human. Please guide me. What if a person gets influenced by his nafs in these situations and then controls himself? Does he also fall into kufr like the others?