
I had a bit of an unusual experience with my crossbred dog - I went to see the litter at 7 weeks and I was the first potential buyer, from a novice breeder.
Out of the six, at first two puppies came running happily up to me and I was allowed to taken them out of their pen and spend some time with them on the sofa with toys etc.
One played with me for a bit then lost interest. The other did want to engage me, so she stayed on the sofa with me, but was busy and not really focussed. Then two others decided I was something worth exploring, so they came out of the pen as well.
One of these engaged immediately and played with the toys I offered him... we had a great game together. When he was put back in the puppy pen he didn't join the others, he laid down ignoring them and just kept his eyes on me the whole time. This was the pup I ended up with with.... apparently he showed no interest in other people who came to view later. I did have a photo of him staring at me from inside the run, fixated (later lost when computer died). The two others out of the six stayed at the back of the run and had no interest in me at all.
I also heard a tale from someone who went to view a pup, and the pup they were assigned to was polite, but another puppy (already booked to go to Australia) kept coming up to the person and ragging their sleeve, demanding attention, in the end plans were changed and the pup who insisted it wanted to be with that person, went to that person and is now a top dog in its sport.
I think it's very special when one chooses you, but it doesn't happen often - you could visit several litters, and not one shows a preference. I found that when going to look at litters of kittens many years ago.
Point being, yes it's special if it happens but that's rare - and it goes the other way too. I have a rescue dog, and the opposite happened there - I saw some photos of her online, read a bit about her history, and knew she was my next dog - even though it wasn't a perfect time and place, it all came together and she is my beautiful girl.