Just as a mother must never have a favourite among her children, a fashion reporter should not allow sentimental feelings to cloud his or her better judgement when it comes to designers.
Of course, though, one does - and for so many reasons. Some designers make for great interviews, coming up with juicy soundbites or controversial quotes that see your story sail on to the front cover of a newspaper, or become the leading feature in a magazine, rather than buried somewhere at the back.
Others talk in riddles, are unable to string a sentence together, or are simply rude or mad. Then there's the type who are far too handsome/beautiful/charming for their own good. Halfway through talking to them you realise you have stopped taking notes. Of course, frocks (suits, shoes, bags, etc) that make your heart sing and cash tills ring counts, but so does personality.
Never more does this become apparent than when a designer is catapulted into the headlines through an extraordinary event like a royal wedding.
Last weekend I found myself at a charity gig with a designer who ranks in my personal favourite-designer-top-five, Bruce Oldfield, the man who is now listed as one of the favourites for creating what could be the dress of the decade.
A day before the announcement came that Kate Middleton was to marry Prince William (who is second in line to the British throne), which kick-started a furore surrounding the imminent Windsor Royal Wedding, Bruce and I talked about what designing a dress of this historic importance might mean to him.
Having been pestered by the press for months, he's adept with dealing with prying hacks. When it comes to personality, Oldfield is a box-ticker: he's got charm, discretion, he's wickedly witty when it comes to interviews and we already know what his gowns can do in terms of putting a woman on the international "one to watch" rota. This is, after all, the man credited with transforming the late Princess Diana into an international style queen with his particular signature old-school glamour.
Wearing an Oldfield allows you into an exclusive club of impeccably dressed women, internationally renowned for their chic, classy but rather glitzy style. Former Bruce brides include Queen Rania of Jordan, Samantha Cameron and Jemima Khan (as well as Wags such as Rebecca Ellison, the wife of the England captain Rio Ferdinand, and trend setters such as Sienna Miller).
The drawback, according to Oldfield (who is 60), is age. Everything about Kate and William is surrounded by youth. By fashion standards, he's no spring chicken. However, Kate will be aware she will be judged on this dress forever more. Although nothing equals the exuberance and enthusiasm of youth, equally there's nothing like experience when it comes to taking a chance with a bridal gown.
Is it naughty to speculate, too, that Karl Lagerfeld or John Galliano might be taken into consideration? Now that would be some dress. Lagerfeld comes from a self-made background, and is certainly fashion royalty. Meanwhile, part of Galliano's Dior revenue, we know, comes from brides, many from the Middle East. I once was a guest at the wedding of a Greek shipping heiress in Mykonos where the bride wore a gown by Galliano created to mirror a type of conch shell found in the Aegean Sea. Nothing has ever compared to what I saw that day, but would his style be too overpowering for Kate, whose look, so far at least is classic.
Although mostly British names have been thrown into the ring (Alice Temperley, Christopher Bailey, Jenny Packham) along with London-based Erdem, it is more likely that Kate will be steered towards couture bridal designers whose clients hail from the leafy streets of Kensington, such as Sassi Holford or Robinson Valentine.
Or might she go for Oldfield after all? Last week, he dressed Evanna Lynch, a star of the new Harry Potter movie, in a short dusty pink number for the premiere in London and put her on the front pages. He's also dressing Sienna Miller and Alesha Dixon.
How pleased would I be if the princess-to-be chose something by him for her big day? Delirious. And one thing is certain if she does: it couldn't happen to a nicer bloke.