UKH

The notion that " all cars look the same" led me to think about climbs and I've been racking my brain trying to think of two pitches I've done on different crags which are very similar almost to the point of being the same.

I've given up. 

(I thought of the three Welsh Corners but couldn't say from experience since I've only done one.)

Any suggestions? Surely there's a Great North Road somewhere else in the UK or even further afield.

You're much more likely to consider routes as similar if they're forgettable rather than if they're memorable, almost by definition.

As such, I'd suggest some things either on Gingerbread Slab or on Rugosity Wall.

Do they have to be in the uk? All grey slabs on Kalymnos are pretty much interchangeable 

I wasn't aware of that. Come to think of it a lot of the slabs at Mello are samey. I take John's point about forgettability as well since all I can come up with are some easy angled slabs on Arran  and a similar route in the Ogwen Valley above an outdoor centre owned by some stroppy navy types. 

When I first started climbing I went to cala gonone and climbed the same prickly grey 6a slab several times a day at a variety of crags.

These days I go on a sport trip and climb the same 7a tufas...