Most interesting: For me, it'd probably have to be the Cambrian Coast Line. I've always loved the line, its uniqueness and its fascinating sights along the way. There's just something so compelling about the scenery en route, having the mountains on one side and the sea on the other. The strange isolation of the route is also intriguing, in that it takes almost 3h 45m to reach Shrewsbury, the first place where the Cambrian Line actually joins up with the rest of the network (barring the Aberystwyth Branch).
Most nostalgic: I'm a bit useless so I have no clue about the type of train, but I do have some fond memories of travelling on the Portsmouth Direct Line onboard slam-door trains. If I remember correctly, I think my first ever train journey was on one of these trains to Portsmouth.
Most boring: I've always found the stretch of line between Sheffield and Doncaster to be quite soul-destroying. Particularly as it juxtaposes the pleasant Hope Valley line if you're on a TransPennine Express service from Manchester. In addition, despite the relatively short distance, this stretch of line always seems to drag on forever, even on one of the aforementioned TransPennine Express services.
Most hated: Purely based on a past experience, Wolverhampton station. After having almost ran all the way from Wolverhampton Racecourse back to the station one evening to catch the last train home, Transport for Wales managed to mess up my journey by cancelling this last train, leaving me with no option but to board a Virgin Trains service instead - the last one - via a different route whereby my ticket wasn't valid. It was a stressful journey, to say the least but luckily there weren't any ticket inspections. I did manage to claim compensation afterwards, however.
And I'm going to add an extra category here as I feel like this deserves a mention...
Most enjoyable: The (or what was) Virgin Trains first class breakfast service. Despite the rather small portions and the possibility of getting turfed out of Coach K on the Pendolinos - which has indeed happened to me - I've always enjoyed the Virgin Trains first class breakfast service. I just really enjoy the idea of being on a long journey onboard a comfortable train (Yes, comfortable, bring on the hate!
) eating a cooked breakfast. I find it incredibly relaxing, especially when you know you're likely to be off to holiday somewhere nice.