Who out there has not done this at some point? haha. I've done it when somebody is talking about a movie I want to see and I don't want it spoiled for me. I've done it in my head when overhearing chronic complaining. It can be a useful tool in a never ending, no win arguement. I've sang the lala's in songs when the writer of it was clearly at a loss for words.
Maybe the 'lala' method would irritate the person who is using unpleasant words as much as their words bother us. There is so much in this world that we should avoid hearing.
Many people shut their ears like this to the gospel but it is not a wise decision. It's just a way of ignoring and refusing to submit to His Word. Romans 10;17-18 'Consequently, faith comes from hearing the message, and the message is heard through the word about Christ. But I ask: Did they not hear? Of course they did: “Their voice has gone out into all the earth, their words to the ends of the world.”' Some people choose to 'lala' thru parts of the Bible too instead of accepting all of it. You can't pick and choose what you like or don't like. Deuteronomy 12:32 ''See that you do all I command you; do not add to it or take away from it.''
I'll wrap this up not with a bunch of lala's but I prefer 'nananana hey heyyyyyy goodbye.'