I first caught a virus in 1991. And it was also the last time in personal level. But professionally, I also caught one in 2001. Here is the story:
I was teaching some basic skills to people who had been asking me to help them learn how to surf the Internet, use eMail, and create and print documents. Despite my preference to Lynx/Mosaic/Netscape and then Mozilla, I wanted to give the students the standard experience -- the stuff almost everyone was using: Windows XP, Office XP and IE6.
I had fully updated and secured the systems with a few policies against unsigned activeX and taught the students to avoid clicking OK to messages that would install new software, despite the misleading text saying "the manufacturer asserts that this content is safe" in which YES WAS THE DEFAULT ACTION. I knew dozens of people who had installed dialers on their systems due to that design, but I thought that if no code would be installed, we would be safe.
Yet after a week, one of the systems had its home page changed into a porn site. It was a virus; the process could be killed only to be revived in seconds. Searched the web and found it was one of the worst viruses ever made; it had injected itself on system files of both partitions; no tools existed to remove it, so the entire disk had to be formatted.
I asked some other guys, who were doing this thing at a professional level, if they had the same problem and yes, they all did. But they figured that it wasn't an issue since the students were at the basic level and they wouldn't have important files to lose. They also wanted to conform to the exams who would require an additional process if an "alternate" browser was taught to the student. I found that unacceptable. Teaching basic skills to people should also have included basic principles. And at the time, avoiding Internet Explorer had to be such a principle.
My problem wasn't that some hacker had found their way to run code with IE. That was simply a mistake from Microsoft. But the fact that Microsoft would allow installation of software based on the message I linked above and considering that IE was the defacto browser of new, inexperienced Windows users -- now that was bordering with either malice or stupidity. Of course things must have changed since then, especially with IE8 and sandboxing, but the problem is not that I have simply lost my trust to IE -- it's that I find it counter-productive to try and get it back. Trusting IE again would require effort which I have no reason to make since the alternative (Firefox) is simply great.
Then comes the issue about standards. Yes, like many others here I've wasted time trying to make pages work in IE6 work the same way they do in Mozilla and Opera. Again IE8 is improved, but when I read people in Slashdot saying that IE6 is the only problem, I smell astroturfing. Hey fanboys, did you check IE8 Acid3 scores lately ? It's worse to what Firefox, Opera and Safari had been ages ago!