Southern England's transport networks are radially focused on London, leaving poor public transport options for many trips that seem like they should be quite simple.
Perhaps the most obvious example for us, living in Oxford, is getting to "the other place" (Cambridge). This involves a train into London, a tube or bus connection there, and then a train out to Cambridge. Which takes nearly three hours (two and a half if the connections all work nicely). The only direct option is the notorious X5 bus, which does at least run every thirty minutes during weekdays, but also takes three and a half hours and is known to make people ill from going around too many roundabouts. (This trip takes maybe two hours by car if there's no traffic: the fastest route is a tossup between going towards London, around the M25, and back out, and a more direct but slower route via Milton Keynes.) There's an effort underway to revive at least part of the old Varsity Line as the East-West Rail Link, which would be a great option if it ever happens.
I've been to Northampton twice to meet up with a friend who's moved there. This is a straightforward drive, taking an hour ten if there's no traffic: only a small stretch of the M40 is useful, but the A34 and A43 provide near-motorway dual carriageway for most of the route. The public transport options here, however, are woeful. One can get a train all the way up to Coventry and then back down, taking up to two hours and costing a startling £42 return (for three people a taxi would be cheaper). Or there are various combinations of buses and trains changing in Milton Keynes, also taking two hours. There is an express bus taking an hour twenty (the National Express 302 service connecting Northampton and Bristol), but it runs only once a day, from Northampton to Oxford at 7.30am and from Oxford to Northampton at 8pm, which is not at all useful for day trips from Oxford.