different situations and industries. in my line of work it is common for an employer to pay quite a lot of money for employees to be educated and usually receive certifications that can make available jobs that would have been previously unattainable due to lack of said certs. as a business owner, i do not want to lose that kind of investment and it is an insult to use my company funds to get hired elsewhere. this is where more granular agreements must be signed before anything. otherwise anything goes and if i neglected to get them to sign but still put them through courses and they got a better job thats my fault.

It kind of depends on your motivation for looking, too. If your boss thinks you are looking for an new job because you don't like working for them, think they're a jerk, or aren't getting paid enough, that could be seen as an insult to them. Kind of an "oh, we're not good enough for you?" kind of reaction.

Yeah my boss hated me. If she knew i was quitting before i put in my two weeks notice she would have fired me right on the spot.

My boss would be sad because he enjoys having all of us, but knows we are moving on to bigger things.