OP: > they stopped saying hello or even talking to me
The OP said they completely stopped talking, which is weird to not acknowledge someone you previously would talk to. Seems like sociopathic behavior to me, which these professions tend to attract. They got what they wanted/needed out of the relationship and now could care less.
Languages are full of phrases that get used so often the original meaning gets lost organs others that are heading that way. Raining cats and Dogs is ancient and nobody is quite sure where it came from, but as long as people understand intent there’s no need for to add up correctly.
Words with opposite meanings can end up converging. ‘That’s cool’ and ‘that’s hot’ sometimes have the exact same meaning depending on context.
But the correct formulation is a shrugging question "I could care less?", with the implication that the care-meter is already pegged at zero.
given how cheap is to say hello, and maybe get some advantage from this in the future, this is not very smart sociopathic behavior.
But this maybe be result of culture differences: some people grew up in culture where work is work(with all protocols, like saying hello to coworker), and personal life (interhuman behaviour) is something separate.
Yeah professions like finance both attract and reward sociopathic behavior.