How to deal with guilt turning down non-tenure track faculty offer at current institution? I recognize my questions have some overlap with this one and this one. I feel those are largely talking about different things, though.

I am in a situation where I have been offered a non-tenure track faculty position at my current university. This is also the institution in which I did my PhD, but the tenured faculty I would be working for is not the person I did my PhD with; I have been working with them since finishing my PhD though. So I feel a great deal of appreciation for the institution and the faculty member I'd be working with.

However, there are a few issues with the position, and I am considering a competing offer in industry that seems to better fit my personal goals. I (and some mentors without a dog in the race) feel  that I would grow more in my area of research in the industry job. The non-tenure track position has been very hard for the faculty to fill, and they tend to lose whoever they hire to industry anyway because industry offers far better compensation. If I accept the industry job and turn down the faculty job, I will still be working with the faculty for a few months. I am not worried about the faculty seeking retribution, or that I will be burning a bridge, especially because I have been open about other offers and my goals from the beginning. Despite that, I still feel a sense of guilt considering the industry offer, and I think that might be clouding my judgement in the decision of which offer to accept.

So the question is as stated in the title, but I can be more specific. I recognize this may not be a question that can be answered with concrete steps, but what I am looking for is how to decline the faculty job in a way that will be palatable and not seen as greedily choosing industry over what I'm offered here.
If they really wanted you (or anyone) enough, they would make the position more desirable (tenure, pay, etc.).  They do it for other positions.

Don't you worry yourself a bit.  Be pleasant on the outside, sure.  But realize this is a business situation.  You have competing offers.  Take the one that does more in terms of pay/etc.  

Also, often to advance in life, you need to move around some.  That's nice that you have a cozy situation there and people that value you.  But move on and do it elsewhere.  It's not unusual for companies or organizations to pay more for someone external than someone internal.  

In particular, it is completely normal for someone in your situation to move on (recent grad).  If anything hanging out at your school is more the oddity.  So nobody will care that you moved on. Will wish you the best.