Like a punch in the stomach
Imagine, for a moment, that you woke up this morning to discover that the country you lived in was being invaded by China, and it looked pretty much like China was gonna win.
You know that the people living in China are good people, happy people. You know that many good things come out of China. But you didn't want to live under the Chinese government. Their system is just fundamentally wrong, contrary to what you believe in, and the government has been responsible for horrific atrocities in the past that you never want to be associated with.
That is what it feels like to be a web developer, working for Yahoo!, and waking up to discover that it looks very likely you are about to be purchased by Microsoft. Microsoft may be a good company, a strong company, maybe even fun to work for. But they don't get the web. Their whole corporate DNA is contrary to the culture of openness and interconnectedness that makes up the Internet and that Yahoo!, despite its many flaws, understands. A Microsoft acquisition of Yahoo! would be the death of Yahoo! as a company and a culture.
I deeply, fervently, sincerely hope that this deal doesn't go through, but it looks like it will, and that's heartbreaking.