What's wrong with intensification?

What is the problem with intensification? I don't think it is that we don't want to live near each other. I don't think that it is that we will suffer from the traditional outcomes of overcrowding -- cholera or other infectious diseases.
I think the problem with intensification is that it is the excuse for anything someone else wants to do at my expense.
I've lived in very densely populated places. When I had an apartment in Copacabana in Rio de Janeiro in the early seventies, this was the second most densely populated place in the world (even greater than anywhere in Hong Kong). Density is not the problem in itself.
In Copacabana there were virtually no buildings of less than 10 storeys (and in my day, only one in the whole area of more than 14 storeys). Now there is a subway line through the neighbourhood and development has gone higher.
But in Ottawa we have a different situation. Here dense development is a prize awarded to a specific property owner who takes advantage of any available infrastructure. That first applicant is granted the privilege to use what infrastructure exists (pipe capacity under the street or space for transportation). Can that single applicant be accommodated? Yes, but any further development will require infrastructure to be reinforced.
So the prize goes to the first applicant. He/she cleans up and the costs are left for those who follow.
Is it over-development or over-intensification? No but it forestalls further development because the infrastructure has to catch up, not at the expense of the initial applicant but of those that follow and of the citizens at large.
For an Ottawa example, what proportion of the development potential of that corner of Westboro was consumed in the development of the Metropole complex? What proportion of the development potential of the area along the north shore of Dows Lake is being consumed by the many tall buildings proposed for there? Who will pay for the Dows Lake subway station needed to cope? Who will pay to rebuild the water and sewage lines to serve that level of development.
Just because I might not want to live on the 45th floor of a building is not a reason to object. But what is the effect of such construction on the surrounding area or on taxpayers across the city?
.Bob