More people cooking/sharing a kitchen, more showers being taken affecting hot water consumption, more persons to occupy one of the couches or tvs, more personalities to adapt with and keep consideration for, etc., plus the utilities you mentioned- water, Wi-Fi, shared amenities such as paper towels and soap etc.I’m not trying to be combative, as your point makes sense.

Adaptability is key!

An approximation of that phrasing works for me, adapt it however suits you and move on.

I've decided that I want to peruse a career where I can adapt what I learn on the job to my own properties and need some help where to start looking.

It forces you to adapt to dealing with a lot of different personalities.

As any savvy real estate investor will attest to, you must be able to pivot your strategies and adapt to the market you are interested in. 

I think as an agent, the biggest challenge I had (other than to get over the idea that "boring" repetitive activity i.e. lead gen doesn't produce results) was to learn how to be adaptable. 

If it’s so awesome, why wasn’t it adapted en mass years ago?

Hedonic adaptation at its finest.  

I would first ask for a new AC, cash at closing for one or something along those lines.The warranty isn't a bad way to go either, just be aware that they don't always replace the whole unit, just the broken parts, and you will have extra fee's associated with what ever they install including haul away, adapters, extra parts, new coolant etc.