I used to open many interesting questions from Stack Overflow (10..80 tabs) in my browser and then read them slowly over weeks. My browser (Opera) knows to reopen the last tabs but I'm afraid it has an aggressive caching mechanism.
By that I mean it shows me I'm still logged in but when I try to post a response or a comment I'm given a strange error message (for example: Cannot add comment because the answer has been locked or deleted) when all that is wrong is that I'm no longer logged in.
Refreshing the page prior to posting (along with re-logging in) solves the problem.
My issue is: shouldn't the error message state something along the lines: "you're not logged in suckaa..."?