A different point of view
I once was offered a job interview by a competitor to my then current employer. I accepted that interview to learn what they might have to offer. In a society where we are not slaves, I think that is perfectly fair. Employment is not marriage, or citizenship, where loyalty is normally a lifetime affair. Employment is at the convenience and for the benefit of both parties, employer and employee.
The competitors offer was attractive, but not a real paradigm change. I received a counteroffer (without even asking for it) and chose to accept it, and stayed on with that employer for a number of years and with no hard feelings. On the contrary, I think they saw it as an added sign of loyalty that I stayed on, and they saw counteroffer as a way to not penalize me for that loyalty, rather than as extra money that I got out of them by blackmail.
The thing about money not being so important works both ways. If they are happy with my work, a little bump in my salary should not bother my employer and can make my wife and kids a bit more comfortable...
