prospective English doctoral candidate: advice regarding weird relationship with potential advisor I recently got my BA in English from a top 10 university and am planning on re-applying to the same school's doctoral program this fall. (For personal reasons, I'm constrained to programs within a certain geographical area, so my application is rather nonnegotiable.) 

I didn't do incredibly well during my first two years, and only started taking myself very seriously in the fall of my junior year. In my junior fall, I enrolled in a large lecture that I hardly (if ever) spoke in. I attended office hours only once, and I remember being really socially awkward/naive, but it's hard to judge the validity of my own memory in retrospect. It's likely that the professor doesn't remember the incident. He only graded one of my papers (the others were graded by the TA), which he returned with incredibly enthusiastic comments. I put an unbelievable amount of effort into it (likely significantly more than anyone else in the class), and my work was excellent.

The issue is this: because I had been a bit of a basket case during my first two years, I didn't really have anyone who could write me a good rec letter. In a horrible lapse of judgment, I emailed this professor that winter break, asking for a last minute rec letter for a summer program I had just found out about. I sounded kind of crazy/manic in the email, which went into unnecessary detail about the reasons why I was entreating this man I barely know to recommend me, and how eager I am to continue to do this work seriously. He sent a quick reply agreeing to write the letter, and I sent a quick "thank you."

Another mistake: I was so anxious about/humiliated by my behavior that I just...never followed up with him. I didn't send him a more formal thank you. I didn't update him on the status of the program (I didn't get in). I have literally never spoken to him since then.

Now, two years later, it turns out that my research interests have defined themselves such that, if I were to be accepted into this program, he would almost certainly be my advisor. He'll definitely be reading my application. 

So the question is: how much of a problem do you anticipate this being? I truly have no idea. And do you think there's any way to rectify it? I'm an entirely different, more mature, levelheaded, reliable person now, and hopefully my application demonstrates this. But frankly, I was rude, oblivious, and crazy-sounding, and that impression of me is not at all the kind of person a department wants to trust with 5 years of funding. I feel like emailing some sort of short apology would also look crazy, because 1) what if he's forgotten about it? and 2) who thinks about this stuff two years later? On a less speculative level: should I mention him as someone I intend to work with in my letter, or should I avoid doing so? Thoughts of any kind would be much appreciated. It's largely silly and minute, but it's really eating at me and I do have to make some practical decisions about the content of my application.

If it helps: I believe the rest of my application is competitive for a top program (4.0 last two years, near perfect GRE verbal, rich cv)
I advise against sending an explanatory email. It will only make the waters murkier. An email can't correct what transpired. A better option is to meet with the professor in person to discuss your plans. This would give you a chance to demonstrate that you've changed and establish a new relationship with your professor. Don't spend time explaining your past failures. In your meeting, focus on what's positive in your record and your commitment to your new plans. Everyone screws up, you know. If this professor has the wisdom of his years and he sees a new spark in you, he will probably want to support you. Take a lesson from the past, forgive yourself for being human, and move on.