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I have been working at my current job for the past year and last month I applied for another job that was located in a bigger city. The team there invited me for two days to for an interview and just learn more about the company and the location. They were very gracious, friendly and I was honestly interested in working with them. Two days after my trip, their HR office formally offered me the position however their salary was exactly the same as my current position (plus relocation assistance) but as the job location was in a bigger and more expensive city hence I declined the offer. Their counteroffer was not enough to compensate the living cost and I did not find any incentive to relocate.
There were two rounds of back-and-forth offer/counteroffer and based on the in-person interview they really wanted someone who knew X, Y, Z technologies. I feel kind of guilty that I wasted their time as they were very gracious during my visit and an in-person interview at the same time I did not want to accept their offer as my original goal of applying for another job was a salary increase.
Should I feel guilty that I wasted their time by failing to bring up the salary expectation during the interview? although I mentioned my current salary in the application and also in the first phone interview.