Mine is a bit universally horrible tbh, there's either a straight run down the A23 (Brixton, Streatham, Norbury, Croydon) which isn't quite as bad as it sounds, but the exhaust fumes can be unpleasant. Alternatively, I can follow CS7 down to Tooting and then across Mitcham Common. In theory that ought to be sound, but despite the CS7 moniker, it's really no better than the A23 and adds a couple of additional kilometres and throws in the Lombard Circus of Death. The most pleasant route is down Walworth Road and through Dulwich and over Crystal Palace hill and down the other side. The last bit features the A22 again for added yuk points and a hill that features the sort of potholes you can disappear down and not be found again. In summer though, I wander up over Kenley Airfield or the North Downs. Or sometimes take the Wandle Trail for a more leisurely and mostly traffic-free pootle. Options are better with the long days.
I guess I'm an 'extreme' commuter, but the majority of streets and roads I encounter are reminders of why cycling will never be a popular method of transport.