Rampaging Toddlers

Kate was in Florida last week for the AVMA convention.  She came back with a Rampaging Toddler story...
Evidently a little girl on the plane screamed the entire time, and also threw violent temper tantrums that involved kicking the seat in front of her.  As this happened the adult nominally in charge of the child did and said nothing at all to either mitigate or apologize for the child's behavior.
Incidents like this are the reason it's taken us so long to have children.  Kate mistakenly (I think) interpreted her reaction this sort of thing to mean that she doesn't like children.  As a number of our friends started having and then responsibly raising children she eventually realized that her issue isn't with children, it's with dumbass inconsiderate adults who have no earthly ethical business raising children (as incontrovertibly evidenced by their public negligence of child raising duties) but have gone ahead and spawned anyways.
This raises the spectre of my biggest parental insecurity...
Why did we decide to have this child?
That's a hypothetical question.  We were pretty deliberate about having the child, and it took a long time for us to get here.  But...
I have this really big issue with people who's children pretty much solely exist to be in service to one or both parent's image of themselves as Parent.  I really don't want to be that person.
Let me tell you about my ex-wife's step-mother (Norm!)...
Yes, for those of you who didn't know about this, I have an ex-wife.  I don't talk about her much; for one thing, I was too young and immature to be married in the first place, for another it was a really long time ago, and she's no longer really relevant to my life in any meaningful way.  But now that we're ten weeks or so away from the birth of this kid I have to confess that most of my list of what not to do when it comes to child rearing comes from my ex-wife's step-mother (Norm!).
This woman had children pretty much solely to satisfy her image of herself as Mother.  The kids were in the realm of four and six, I think, when we split up eighteen or so years ago.  They seemed like okay kids then (in spite of...) and hopefully they've become okay young adults.  I have no idea whatsoever.
In any case, when these kids were little they were phenomenally over-indulged in a lot of ways because their mother (Norm!) ran every action and decision through the filter of what would serve her image of herself as Mother, not through the filter of what's best for this kid.  So any time anyone, including my former father-in-law, said "no" to one of these kids for any reason she would swoop in and grant whatever thing or behavior had been denied on the basis of...  I honestly have no idea what was the basis of this behavior, except that she clearly reveled in being the Champion of Her Children to the point that the need to be so completely replaced any semblance of rational thought.
True story:
One of the last times I was in their home (maybe the last time) I helped my former father-in-law mount some new curtain rods in his bedroom.  The youngest child, a boy of probably four, wanted to play with the drill that we were using.  Dad [appropriately] told him that this drill wasn't a toy.
Kid screams and cries.
Dad stops what he's doing and goes to where the toys are stored and brings back a toy drill for the little guy to play with.
Not satisfied with the toy drill when the real one is so much cooler (it was), the kid continues to scream and cry.
Dad and I proceed with the installation of the curtain rods as the kid stands in the room and wails.
Step-mother (Norm!) walks in and asks why is he crying?
Dad explains that he's crying because he wasn't given the live cordless drill with the actual wood penetrating bit in it to play with.
Step-mother (Norm!) says (in a clearly disapproving tone)...
wait for it...
"I think you better give him the drill."
Which...
He does!
This, of course, completely stalls the curtain rod mounting project.
Step-mother (Norm!) goes back to whatever she was doing.  I don't remember what my ex-father-in-law did next.  I do remember watching the four year old with the live cordless drill roam unattended into the living room and proceed to start drilling holes into the white leather upholstered living room furniture.
I do recall that my ex-father-in-law wasn't surprised nor appalled at the impromptu remodeling of his very expensive living room set.  Nor did he make any effort to take the drill away from the child.  The child could have just as easily proceeded to drill holes in himself or someone else, of course.  That would have been funnier, but no more likely to produce a disciplinary reaction.
This was sort of an outer edge example of a fairly common sequence of events in that household.

That's my parenting nightmare.  Will I be so clueless about the intersection of my kid and the rest of the world that I'll be oblivious to inappropriate, disturbing, or even dangerous behavior displayed by my kid?
I'm not asking for reassurance here, by the way.
I'm pretty certain that being aware of the potential problem, and having such an amazing example of how not to do it, will prevent that.
There's probably a bigger chance that I'll err in the other direction, and not let the kid be a kid, but that's a bridge that I'll jump off of when I get to it.
Kate saw the doc last week, by the way.  Everything is still on track and looking good.
Also, we finished everything but the plumbing in the remodeled part of the basement.  We also bought a bed for the guest room that we have to assemble.
And we think that we've settled on a type of diaper.
No progress on a name yet.  We might just have to see what he looks like when he gets here.