Labs are lovely dogs and wonderful company - we have a 2-year-old chocolate lab bitch who I love dearly. I, like you, do not enjoy going out of the house, and I hardly ever walk the dog BUT dh walks the dog every day, twice a day at the moment, and ds1 walks her too, plus our neighbours have a lab who is her best friend, and they will take her out when they take their lab out (and we do the same), so she is getting enough exercise.
She was hard work as a puppy - she chewed everything, had loads of energy, and needed lots of entertainment and stimulation. It is good fun, but it requires an awful lot of commitment.
I would say that I wasn't desperately keen on getting a dog (I grew up with cats and was really iccckk about the idea of picking up dog poo, and about the 'doggy' smell), but Coco has entirely converted me. She has calmed down an awful lot, and is a wonderful companion for me - the boys are all at senior school, so I am alone in the house a lot, and she follows me round and snuggles up to me wherever I am. She is just a solid bundle of love, and I couldn't be without her now - and I can't imagine being without a dog either.
We have a cat who is about 6, and he really does not like the dog - but although the cat is the size of the dog's head, the dog is scared of the cat, and will back off if the cat looks at her. She will even refuse to go close to the cat to get a dog treat or food (and if you know labs, you will know that not gobbling up food that is offered when it is offered, is practically unheard of behaviour). However she does love the cat's food, and we have put a stairgate at the bottom of the stairs, so the cat's food is upstairs, and therefore safe from the dog (as long as people coughcoughdhcoughcough remember to shut the gate).
We also cage-trained Coco, and that has really helped - her cage became her safe, comfort space, so she was always happy to go in there. She went in there overnight, and after the first couple of nights, she never soiled her cage, so it was a big help in housetraining her - plus she learned she could go out through the cat flap whenever she needed to wee/poo. I did think I'd find her stuck in the catflap as she got bigger, but she somehow realised when she reached that point, and now instead of going out through the catflap, she rattles it with her paw to tell us she needs to go out.
I also have to say that I am utterly
with jealousy, as I would adore to have another lab puppy (or even just a litter of pups that I could go round and play with until they went to their forever homes). Please don't post pictures, as I will become unbearably broody!!

