* What breed is it?
* Is it a boy or a girl?
* How old is it?
* When are you going to have it neutered?
This exchange made me query the assertion that "Having a dog is like having a baby" because whilst, yes, the first three questions are often trotted out when you're out with your baby, that final one is definitely not something you should ask a new parent.
Anyhow, we took the decision to have our Vizsla, boy, 18 month old dog 'done' on account of the fact that we didn't plan to breed from him and certainly didn't want the singularly terrifying spectacle of our dog getting stuck inside a lady dog. Especially as we never go on a walk with a bucket of cold water which is what I seem to remember you have to use to separate animals that are locked together.
So we booked the boy in and after a few hours at the vets he was ready to be collected and brought home. We were told that in no uncertain terms was he allowed to get at his stitches and to keep him as quiet as possible which is a big ask of a dog that likes to run several miles a day. Now, the question that most people ask after a dog is castrated is "Has it calmed him down?" but before we even get to that, you ought to know what can happen immediately after the operation:
Your dog will make it his life's work to get at his 'wound'
Never mind trying to lick non-existent balls, what he wants to do is get that dressing off because it is sticky and probably a bit itchy. A Buster Collar or 'Cone of Shame' will work in some instances but you may also find that it makes your dog stand stock still in the middle of the living room panting and whining for hours. Which will make you feel bad and so you will buy an inflatable collar instead.
The only issue with the inflatable collar is that if your dog, like my dog, has a long neck, then he's going to bend it gracefully and give himself a good licking. You will wake up one morning to find that the dressing has disappeared and quite possibly been eaten. You will think he may also have eaten his stitches and made the wound worse which will cause you to photograph your dog's genitals on your phone to send to the vets (and thank your lucky stars that you don't sync your photos to the cloud). The vet's response will be "You need to come in for another dressing."

As nice as it looks, your dog may decided that he does not want to wear an inflatable collar and a babygro and will rub himself vigorously along the outside of your house so that he puts holes in every item of protective clothing that you have shoehorned him into. That said there is something satisfying about another species discovering the complexity and discomfort of clothing with poppers.

Your dog will injure himself
Because your dog has been on restricted walks for around two weeks he is going to go absolutely batshit the minute you decide that he's ok to go on an off-lead walk. This will involve him catching a dew claw which will bleed quite a lot. But this is not as bad as you initially anticipated and it will fall off, healing up rather nicely on its own meaning that you can resume your walks and runs because frankly you could do with the exercise too given that you've tripled your calories in the run up to Christmas. But it turns out that you've been a little too confident because:
Your dog will injure himself. Again

This removal of the dressing will necessitate a quick fix involving a sanitary towel, some vet bandages and a rubber glove before another visit to the vets for a proper dressing. And a new buster collar which miraculously he will tolerate this time. You will think this is amazing because it means that you can leave the house without fear of him taking off his dressing and re-opening the wound.
So you will go ahead with a lovely lunch you have planned with your husband where you will want to drum your feet on the floor because the food is so delicious and you'll have grown up conversation and some decent wine. And you'll get home all happy and giggly to discover that because of the magical buster collar the dog couldn't see where his water bowl was and instead of putting his face into it to have a nice drink he'll have put his bloody foot in it. Which means you have to go back to the vets for the second dressing in the space of a day. And sleep with your dog overnight because you're petrified that he'll figure out how to get around the buster collar which means that he will lie on your chest and place his cone head directly on yours creating an extremely uncomfortable, sweaty sleeping arrangement.