Oh, please. You were unclear and, I think, still a bit in the wrong regarding the way you're handling this situation.
Just be careful in the way you interview and network. You have to look out for yourself, but burning bridges is never a good thing. When you are receiving job offers there is absolutely nothing wrong with expressing excitement/interest and saying, "let me discuss it with my family" or "when do you need a decision?" But for those of you criticizing RoJoHen, understand that there is no such thing as a "job offer" until you sign on the dotted line. Anything else is an empty promise, and it's not worth learning that the hard way. Second, he has every right to accept a job position and then accept a better one a month later-- but it can have consequences. This happened a lot at my last job, when people would come in for a month-- do little more than train for the position, and then leave when they got their security clearance. Huge human resources hassle that means more work for everyone else. We largely understood, but it still would make a huge mess of things-- you can't be ignorant to how it could hurt the company you've just started working at.
To be clear, I was not suggesting otherwise. I merely clarified that the reactions of Timby and T'Baio might have been warranted at the time they posted them, based on the information (and how it was presented) from Rojohen. Rojohen freaking out about it though is an entirely different matter.
They do have magical properties, you know. I more or less did that. It has a way of forcing you to think very carefully about whether it's the right life path for you. This. Regardless of the later clarification from RoJoHen, I don't think there's anything necessarily wrong with giving a yes to several companies if they're unrelated to each other. Nothing's final until you sign. And even then, it depends on the contract. Where it becomes a highly dangerous practice is when the companies are all in the same field or in a small geographical area or you do it repeatedly i.e. where there's a chance for bad word of mouth about you as an employee to spread. People talk. It can be viewed as untrustworthy behaviour due to the disruptive effect it can have on firms. But if they're unrelated companies or jobs where there are zillions of candidates with high turnover anyway, it's less of a problem. Bottom line, I'd suggest, is put yourself first in the process, but with awareness that this includes managing your personal brand over the medium and long-term as well as the short.