Flight attendants, just do your job - don't you dare try to entertain me

I have pinpointed the exact moment when I became a grumpy old man - this morning at 7.15.

It's when I saw the video of the Air New Zealand crew member singing over the intercom to a captive audience.

Now, it has nothing to do with the flight attendant himself. He had a great voice and belted out Amazing Grace in English AND Japanese (show off - arrgh, see the grump comes easily now). He was a huge hit - so good on him.

No, it was the thought in my head that, "I hope it never happens on my flight. Don't you dare try and entertain me - just do your job". And there it was - I became the travelling grouch without ever leaving my office.

The fact that the performance followed another recent Air New Zealand chanteuse led me to think that flying through the air is now going to be a mile-high version of New Zealand/America/Azerbaijan's Got Talent.

Australia and New Zealand has been relatively safe from aircrew doing their level best to audition for agents. The US and Canadian airlines, however, are awash with comedians who think the safety briefing is a 2-minute try-out for their own Netflix stand-up show. And as we all know, "entertaining" safety videos have a mixed history anyway.

A couple of years ago AirAsia crew left many scratching their heads when they decided a "moaning" contest was the way to entertain. European airlines used to play the paper towel game where passengers had to pass the rolls from row to row and avoid breaking it. Enforced fun - the horror!

A recent study pinpointed the worst age for the mid-life crisis - 47.2. That means I have another year to delve the depths of grouchiness. Researcher David Blanchflower, an economics professor at Dartmouth College, said a host of variables such as career and finances are behind this sudden drop in the "happiness" curve.

Neda Gould, a clinical psychologist and director of the Mindfulness Program at Johns Hopkins, said reflection on the past is also a factor. "We're looking back at experiences we may regret, and then we're looking forward and wondering what the next phase may look like. That can cause anxiety," she told CNBC Make It.