It's worth remembering that Andy gets a lot of praise from some quarters, including journalists, because
he doesn't give glib answers and because he refuses to bend to the social insecurities of others. There is definitely an issue in this country of people not seeing beyond the tabloid personality, but that's not just a problem Andy faces. He's had it worse than many, but it's not unique to him. The fact of the matter is that Andy is naturally an introvert, and there is nothing wrong with that. More to the point, if you are naturally introverted, pretending to be extrovert is very, very hard work, and doesn't actually work. The odds are, you'll come across as insincere.
Similarly, some people's "absent" expression is to smile. For others, it's a neutral expression, which is interpreted incorrectly as being glum. To sit and remember to smile for the sake of it doesn't "cost nothing". Having said that, Andy does smile quite a lot, but now that he's got a reputation for never smiling, photo-editors like to pick photos of him not smiling, and it perpetuates the myth. It's a bit like Posh Spice. She has a reputation for never smiling, yet the people who know her insist she's funny and often smiling. She jokes that they will take 100 photos of her, and print the one where she looks most miserable.
And yes, he wasn't "missing" from the Olympic parade, although I grant you I saw a few hard of thinking having a got at him for that. He prioritises his training ahead of a showbiz bash - so what? It might lower his chances of winning the award, but a lot of people respect him all the more for it. Probably not the sort of person who votes in SPOTY, but again - so what?
The inner circles of Andy and Lendl don't "have to" convince the rest of us they do have a humorous and friendly side to their personalities. Some of them choose to, as do journalists and those who have worked with them, but that's because it's what they see in real life, and it isn't matched by what they read. It's what I see too, because the evidence is all there to be seen if you aren't too blinkered to think that anyone who doesn't act like Gazza is a miserable git. Andy has a dry sense of humour, which isn't to everyone's tastes, and far too subtle for some to even spot, but some of us think that slap-stick is banal.
Speaking of which, perhaps now is a good time to post a link to this brilliant Charlie Brooker piece from the Summer, which I presume was posted at the time, but seems pertinent now.http://www.guardian.co.uk/commentisfree/2012/jul/08/andy-murray-not-miserable-just-normal
At the end of the day, Andy is a professional tennis player, not a children's entertainer. And while Gazza may have been super-popular with the tabloids and general public, a real "man of the people", it turned out that he suffers from severe depression, alcohol addiction, and was violent towards his wife. Gurning for the camera is not guarantee of character.