UX Quickie: Twitter's Alzheimer's

This happens to me at least once a week.

1. I check my email.
2. I get to an email telling me about a new follower on Twitter.
3. I decide that I want to follow back and click on the link Twitter has put in the email.
4. When I arrive at Twitter's website, I find it's been long enough since I last did this that I'm not logged in anymore.
5. I click the "Sign In" drop down and sign in.
6. Whooooooooooooosh I am magically transported to my twitter home.

Ok, great. Now how do I get back to where I was? I know, I know, all of you people are screaming "Click the Back button!!" - but would you believe that I only thought of that just now as I was writing this paragraph? What I always end up doing is going back to my email, clicking the link again, and then finally clicking the follow button. (Users are weird, idiosyncratic creatures and, apparently, UX professionals are no different.)

In my confusion of being whisked away from where I was, I lost my bearings and went back to where I started from to correct myself instead of taking the simpler way out and simply clicking "back". Why? I can't say for sure, because I don't know what my subconscious is doing (and because I'm no psychologist), but my amateur diagnosis would be a fight-or-flight style response happened; I got confused and lost, I panicked a bit, and I retreated to familiar territory without stopping to think about what I was doing.

Twitter, I know you're all focused on your pretty redesign and all, but adding in a requestingPage variable to your Sign In mechanism and then depositing the user back there when done might take you all of a day and would be much better UX.