My first lakeland terrier could climb and open doors. He could get through the teeniest gap. He chased next door's cat through the hedge, into their garden, through their kitchen and up their stairs, where it scrambled to the top of a wardrobe.
When my second lakie had her first season, he went to stay with my friend, who had 2 Tibetan terriers.
All the dogs got on well, and he was shut in the utility room with them at night when friend and her husband went to bed. They used to hang a board across the (closed) utility room door, because one of their dogs would scratch the door to fuck if there was thunder or fireworks.
My boy managed to unhook the board, which neither of hers had ever achieved. He managed to open the utility room door, which was properly shut and had a round doorknob. He opened the kitchen door, which was the same. He went up the stairs and opened their bedroom door, jumped up onto their bed and settled down for the night, as if it was his right to sleep up there with the humans rather than downstairs with the dogs.
He also shat on the bumper of a Merc in the car park of the park she took them to, whereupon she walked away and pretended he was nothing to do with her. 
He once peed on a policeman's boot when we were watching the Boxing Day hunt set off. He used to hate me being on the phone, and would climb up the front of the rolltop desk and run off it with it when it rang, unless I got to it first. He rolled in the stinkiest thing ever - a huge puddle of foul liquid that was seepage from a farmyard muckheap (this surpassed the stench of long-dead fish, excavated from a Cornish beach, that was his previous stinkiest thing ever). He would jump onto the lap of any stranger he liked the look of, if they happened to be sitting down and I wasn't paying attention. If allowed on women's laps, he liked to put his head between their tits and rub his forehead on their chests. 
But he was lovely with people, and brilliant with children, perfectly behaved around horses and cattle and altogether a delightful soul. The friend that he joined in bed described him as "The naughtiest, cleverest, funniest, sweetest dog I have ever met".
I do miss the little sod.
We still have a lakie bitch but she's 15, so not really up to naughtiness any more. But she's been a much easier dog, the only time I've ever been embarrassed by her was when she chased a pet duck that came out of a garden and crossed the footpath we were walking along. The duck was huge, and she is small, even by lakie standards, but the baggage still managed to get her gob round its neck even though she was on the tips of her paws. We couldn't catch her and she was beign dragged around by the panic-stricken duck, until the duck's owner managed to push her off with a rake.
I was mortified, apologised profusely and gave my phone number so the duck's owner could contact me and undertook to pay any vet's bills etc. She rang me that evening, to say the duck was fine, just a little shaken.
I've always kept her on the lead whenever I can see, hear or smell sheep, poultry or ducks, but like the other lakie, she's brilliant around horses and a very respectful of cattle.