You said: "after seeing NYC, SF and Las Vegas, I passed on an opportunity to go for a week-long business trip to Seattle. Even though I had the time, I imagine Seattle being just *mostly more of the same (an uniform, boring city consisting of XX century architecture built on a grid*"

You later changed to "worth it" because you didn't want to admit that these places might not be "more of the same", because they aren't the same at all.

I suspect you also realized that if you find yourself "bored" in NYC, the problem is not the city. There are few places in the world with more things you can do 24/7 than New York.