But is that really in your best interest?
The way this is stated this is how it breaks down:
- I have a better job opportunity (all things equal meaning presumably there are nice people at that job as well at least potentially) that I have passed on.
- The people at my current job are nice to me and/or my boss is nice to me and/or is not an asshole
In the above case it seems that you have been disadvantaged by a loyalty that isn't based on anything concrete simply because you like the people and/or the way you are treated.
Under that premise you might be a programmer at the local small 10 person wholesaler and have a great boss and a great working environment and/or a sense of loyalty because of how well you are treated. And completely miss an opportunity (assuming of course such opportunity is important to you) to work for a much larger company with much more opportunity. Or take someone teaching at a small community college who passes up a potential job at a major university (once again assuming that is a better career path).
My point being that loyalty and a nice environment and the people that you work with are certainly great benefits but can also be in a sense golden handcuffs from progressing further in your career.