I think emotion and pressure to earn was driving me towards doing a deal with too little room in it.

My partner and I both agree that it would be too risky to even forego a loan and purchase a property using all cash without some form of temporary hazard/liability insurance (until it reaches a point where a standard insurance policy could be issued).

It's easy to get emotionally invested and make a bad decision.

I have walked into a couple properties and two strong emotions come to me: i) just felt like there was no way I would live in those properties and ii) i had no idea how much it would cost to get it to a minimum level of 'inhabitable'.My main question is: How can I quickly 'calibrate' myself to be able to reasonably estimate costs of home-improvement job(s)? 

You can seriously hurt the seller financially and emotionally if you don't follow through on what you say you'll do.

Do your research on your investments and do not let any emotion to make your decions.  

We made the decision to purchase it (an emotional one) and spent a lot of money fixing it up. 

He suggested rather than weigh my emotional comfort level, try to look at it as a business opportunity.

When dealing with motivated sellers, keep in mind the motivation is usually emotionally packed.

Always keep your emotions in check when you are investing!