"... A nice collie or golden retriever, attractive looking dogs who aren't dangerous would be ok. But dogs like pitbulls are meant to be guard dogs so should be at home guarding the house while you're out."
Luna, you do know that "nice collie[s]" and "attractive looking dogs" are... well... dogs, right? They have the same jaw structure and sharp pointy teeth as "dogs like pitbulls" (which that gorgeous pup isn't; being a bull terrior, an' all) do. They have the same reactions to noise, stress, intruders, children poking them as the dogs you seem to think should be guarding their owners properties.
Collies, in particular, are classed as working dogs - they're meant to herd cattle or sheep, not simply to sit anywhere looking pretty. They have intelligent brains and, in my experience, get very bored/hyper, very quickly. Not to mention that most of the golden retrievers I've met, get very grumpy as they age. Probably because they're annoyed by simply being coo'd over as "attractive" and "gorgeous" by shallow people who don't understand how a dog's brain actually works... The ones I know/have met on walks... I'm incredibly wary of their personal bubble and their sharp, pointy teeth. One of them is stick-possessive, to the point where my mother's GSD glanced in the direction of the stick in his mouth... and the GR snarled and slathered as though he thought he were auditioning for the part of a werewolf in a horror movie. I actually remember wondering if his eyes were going to turn red, too, at one point. His doting owners won't leave him anywhere - he's their surrogate child and they confess that he's "horribly spoilt". But he's "attractive", in your estimation, so therefore cannot possibly be vicious... right?!
I grew up around dogs - big dogs and little dogs. GSDs who you'd class as being expected to be left at home, guarding my parents home... except, they also get very bored, very quickly and would have seized upon the opportunity to destroy my parents belongings (weirdly, they didn't destroy my toys - although my cute little lab/whippet cross once worked out that if she stood on her head and angled her arse over my toybox, she could crap in it! She also became very grumpy as she aged, and was very adept at giving warning bites when she got tired of my company). Fortunately, she died before I had children - because I wouldn't have trusted her around a toddler at all. My parents GSDs, on the other hand, were both gentle and very protective of me as I grew up. My own GSD, who was elderly and arthritic when my daughter was a baby, used to sleep by her cot at night and follow her around as she learned how to crawl/toddle. He became my baby's dog, essentially. The cross between my head-standing crossbreed and my GSD, though? Incredibly grumpy. Didn't leave him alone with my daughter for even one microsecond. Chances are, he would have bitten her (he had a few health problems, but was "gorgeous" according to shallow opinions, yet guarded my home like a trooper! Hated the postman, for example, and once saw off someone who was trying to unlock the front door in the middle of the night, by pretending to be much bigger than he actually was, through mimicking a rottweiler's snarl...). My elderly GSD? The one who ought to have been guarding my home? Because even though he was beautiful, he was nothing more than a "guard dog"? Snoring beside my baby's cot. I don't think he was even aware that we had a few policemen in the house, to be honest. Totally oblivious and left the guard dog behaviour to the "attractive" little dog with the grumpy streak...
I now have a retired working gun dog (springer) and a Kokoni (essentially a Greek mix-of-who-knows-what). Both get very bored, very quickly, because they're used to being worked - but both are "attractive" so draw a lot of (often unwanted) attention from strangers. As their owner, it annoys me when I'm trying to train them and have to fend random strangers away from touching them as they sit beside me, or children attempt to play with them as we're working on recall or retrieving. My little dog adores children... but suffers from Small Dog Syndrome, so jumps in an effort to look bigger than she actually is. Many children love this... but their parents (understandably) don't. I'm not a fan of it, either, but I'm expected to have a "cute" little dog who is impeccably trained at all times, even though their badly trained offspring are waving sweets and balls right in front of her, and usually screeching at the top of their lungs... My springer isn't a fan of children, because whilst my son was at primary school, and he was sat patiently by my side outside of the school gates... badly trained offspring of oblivious parents/minders would attach themselves about his neck like screechy limpets. His ears and the ringlets of fur cascading down his chest, were apparently just too much for them to resist... I had to change our afternoon walk's routine simply to avoid taking him after a few weeks of this constant "oh, he's so cute!!!" reaction to his general gorgeousness - because I was very aware that, although his training is impeccable, he is but a dog... and the only child he actually likes? Is my son. Who loved being able to walk with his dog home in an afternoon (and I learned a lot about his days as he rambled happily away to his dog on the walk home). They guard my property, they protect my family... but technically, by the above standards of dog, they're "attractive" and therefore simply window-dressing. They're not meant to behave like dogs at all, I guess, just look pretty... except I'd not like to be on the receiving end of their pointy teeth if a stranger tried to enter my home in the middle of the day or night. At all.
Because they're dogs.
They behave like all other dogs can, will, do.
Having said all of that... I'd not like to eat in a cafe where there were loads of dogs, either. Or cats. It would make me feel too nauseous to eat or drink anything. I live with both cats and dogs - and they are kept out of my kitchen and away from our food on the table. Even so, I've been seen to pull an offending strand of fur from my food every now and then... because as a PP said: the stuff gets everywhere. Assistance dogs are one thing - guide and hearing dogs, for example - because they lie quietly under tables and you can/do forget they're there. They're trained to repress their natural instincts - but other, ordinary dogs? Aren't. I know for a fact that my little dog would spend the entire time trying to get onto a lap, or shove her body behind my legs... because a situation like that would terrify her. And a frightened dog is a dangerous dog. My spaniel? Would simply look pathetic in the hope of getting some illicit food from whoever (he can be quite greedy). Which would spoil my enjoyment of cake and coffee, and make others feel guilty as they strove to ignore his cliche spaniel eyes... 
Dogs are wonderful, funny, clever creatures... but they're just that. They're animals. And therefore completely unpredictable.
Even if they're absolutely stunning to look at and have been trained to within an inch of their lives...