Miranda Hart has come in for criticism this week from reviewers who felt that some of her jokes in her arena show did not ring true. Brian Logan of the Guardian was particularly vitriolic, giving Hart two stars and saying that "Several anecdotes ring patently untrue, and when she starts joking about how parents should behave to their teenage children, you think: whose life is this material derived from?".

This has made me think about the whole issue of truth in comedy. In the pre-alternative days the usual mantra was "A funny thing happened on the way to the theatre" and audiences all bought into the fact that the performer was saying the same thing about the same issue every night from Glasgow to Gloucester. But one of the key credos of alternative comedy was honesty. When you did observational stories they had at least to be rooted in your reality. 

Miranda Hart's old school variety style harks back to the pre-new wave days – she even plays Morecambe & Wise's Bring Me Sunshine over some filmed sketches at the end of the gig – so I am prepared to make more allowances than Logan. I found her funny, but at times I didn't quite buy it either. If changing the duvet cover is the hardest thing in her world then she clearly has a pretty soft life. And did she really fall off a toilet seat on a train and right out of the toilet door? And in front of the queue for the buffet? Possibly I guess, but we've all exaggerated incidents to make ourselves sound more interesting, maybe she does it to make herself more funny.

Sometimes comedy is all about embellishment. Maybe Hart's embarrassing incidents happened, maybe they didn't but they nearly did, such as her story about accidentally picking up a "dwarf mother" by mistake at a children's party. I can well imagine someone accidentally nearly doing it and stopping, no pun intended, short, but who is so absent-minded they would actually do it? Well, maybe Hart did, who knows? But it was a story more in keeping with her sitcom character and one of the things about her live show is that it is closer to "her" than it is to "Miranda". There was, for instance, almost no falling over.

Some comedians trade in truths, some trade in half-truths, some trade in fantasy. When John Bishop talks about squabbling with his teenage sons I've got no doubt that there is more than a grain of reality in the anecdote. But when Tim Key talks about threesomes and an intriguing encounter with One Day star Anne Hathaway in his current show I presume he is enjoying a flight of fancy.

There are ways round this dilemma. I was listening to Newsquiz – don't start – last night and Holly Walsh told a story about a friend who worked in a pizza restaurant. When he was bringing a meat feast out from the kitchen he picked some pepperoni off the top and popped it in his mouth. When he got to the table the people he was serving looked at him in horror. It was only then that he realised a long string of mozzarella was stretching from his lips to the plate he had just pinched his sausage from. Walsh made no attempt to claim this happened to her and the story was still very funny. Though whether it would have worked so well in a stand-up set when we expect first-person material I don't know.

Of course, in the end we have to come to Daniel Kitson, who is all too painfully honest onstage. When Kitson said onstage that he has wanked into a fireplace I had no hesitation in believing him. In his current theatre show he talks about the loneliness of his life and I assume he is being candid.

I find all of these types of comedy funny. It is just that some hit harder and carry more than just a laugh with them. It's the difference between fast food and gourmet cuisine. Miranda Hart is great for an instant giggle, Daniel Kitson speaks more from then heart. It is pretty obvious which performances will linger longer in the memory.