It's a common belief in Silicon Valley, and the tech world in general, that companies should "eat their own dog food", which is just a way of saying that a company should use its own products. While this makes sense at some level -- you shouldn't sell something to customers that is unfit for your own use -- the concept of NIHS is similar but takes the line of thinking to the extreme. In this sense, the term is generally used negatively and would refer to somebody whose decision-making skills are put into question because of this bias.

Explanations (and the emotions) for NHIS include:

• Not valuing the work of others (pride, in a negative connotation)
• Fear from not understanding the work of others (lack i confidence)
• Avoiding, or unwillingness to participate in, a "turf war" (cowardness or avoiding conflict)
• Fear of a competitor’s strategies, e.g. aggressive action in attempting to buy out a supplier thereby creating a captive market (fear of competition)
• Fear of future supply issues (fear of uncertainty)
• Being convinced that there will be benefits to "reinventing the wheel", because of securing a more controlled market share (greediness)
• Jealousy that existing products, knowledge, research or service were not created first (jealousy)
• The belief that internally developed solutions would be superior (pride, in a positive connotation)
• Rejection of the belief that "The customer comes first." (selfishness)