There are a few things to consider if you're thinking about real estate investing in general or house flipping in specific.
Treat this like a business, not a play.
It's important to keep in mind that this is a company. You're not buying real estate to make friends or appear nice. You're in this business to make money.
Keep an eye on the market. This is a critical point. During the recent near-collapse of the housing market in the United States, many 'flippers' lost their shirts. The truth is that the warning signs have been mounting for years.
Allowing things to get personal is not a good idea. Always do business without getting emotional attached.