Last Night's Viewing: Cherry Healey: How to Get a Life, BBC3The Secret History of Our Street, BBC2

I don't know quite how I've reached my advanced years without encountering Cherry Healey before, though it's possible that my advanced years have a lot to do with it. There's a presenter out there for pretty much every age demographic and I'm guessing that Cherry – a cheerful young woman who seems very popular with the BBC3 commissioners right now – is marked in the files as "25 and under".

Her niche is the personal experience documentary, which is nice work if you can get it, since it appears to consist of padding out what you were planning to do anyway with a few extra interviews and a bit of direct-to-camera musing. Her previous films include Cherry Goes Drinking, Cherry Gets Pierced, Cherry Has a Baby and Cherry Gets Married, though it's possible that I haven't cited these in order of appearance.

Having Had the Baby and Got Married, Cherry seems to have eased off a bit on the have-a-go element of her journalism. She was very cautious when trying laughing gas and declined to take a puff of salvia at all. Indeed, there were times in last night's film – Cherry Healey: How to Get a Life –when her only investigative resource appeared to be to turn to camera and pull an oo-urr face. She gurns very fetchingly, as it happens, temporarily twisting her face into a comic mask so that when she relaxes again she momentarily looks twice as pretty as she usually does. But this gesture – which, depending on context, you can translate as "What have I got myself into now" or "This bloke's bonkers" – couldn't really be said to penetrate very deep into the issues.

As Cherry phrased it, the issue was "Are We All Addicts?", but her case histories involved a mixed bag of legal highs (laughing gas and salvia) and personal problems (impotence, low libido and body-image). The format involves her first visiting her subjects on site where she chats to them and then, for reasons that never became very obvious, waiting a few days and having them come to her London office to curl up on a sofa and talk some more. And it may be that her best asset is her unthreatening niceness, which encourages people to share what might otherwise be regarded as private matters. The young Welsh man with impotence problems (later cured by a single session of hypnotherapy) certainly seemed to regard her as a new best friend, as did the married couple who road-tested a sex-shop libido pill for her.

As it happens, though, it was only the woman obsessed with celebrity diets and fat-burning pills who provoked something deeper. "How much do you hate bikini-trying-on?" Cherry asked as they did just that (a very characteristic Cherry interrogation). Susie answered by bursting into tears, and Cherry's empathy for her distress was unquestionably the real thing. Later, Cherry confessed that she'd gone out to buy the very diet pills she'd question on camera, and that while she wasn't still taking them she hadn't quite been able to bring herself to throw them away. She has a genuine quality at such moments that explains how Cherry Gets Another Commission.

I don't know whether The Secret History of Our Streets is an exclusively metropolitan pleasure but for London viewers it's terrific, an exercise in social topography that builds on Charles Booth's famous map of class divisions in Victorian London. Last night's episode was about Portland Road in Notting Hill, a street that has £5m houses at one end and council flats at the other. It was packed with wonderful archive footage and will become wonderful archive footage itself, a telling study of prejudice, property-madness and economic division. I'd love to know more about Henry Mayhew too, a disenchanted trust-fund type who was selling up to go and live in the woods. If you missed it, catch up.

Twitter: @tds153