In his recent blog post, Jeff Sauro writes about common and burdensome interaction practices associated with websites and software. Many of them are examples that I've encountered as a user but had never really considered from a usability perspective. I think that to a certain degree I've come to just 'accept' these hassles as part of the experience. I've resigned myself without having realized it.
I think there also may be a bit of professional "oh well, I understand" going on. For instance, in relation to Sauro's #1 gripe, I work at a university and understand the challenges of a user-friendly universal single sign-on across tools and services. So when I'm using my ISU tools I'm only slightly annoyed that my sign-on info is different in some key places that I access frequently.
I can use my ISU username and password to get into WebCT or Blackboard and also CyMail. But I have to use my numeric University ID and a password to get into AccessPlus. And if I want to use the Libraries resources, I've got to have my Borrower ID and a totally separate PIN.
So I understand Sauro's point. And from a user standpoint, I am annoyed. But I also find that, as an IT person, I understand the technical challenges that lead to these decisions and it's not always easy or even possible to make the user experience more effortless.