I'll go with a little redundancy for effect. Here it is...
Going back to Sr's really did suck. It makes you think, "Jr's can't be that easy if you feel so bad about having to go back to Sr's." I hated the fact that you were continually reminded that this is your 7th week at OCS and you act like you're on your 1st day. Meanwhile, you had no 7th week benefits and the atmosphere would continue to be like the 1st day for weeks to come. The games definitely got old, and were played far more often in my opinion.
There are a couple of pivotal moments I'll readdress, that were mentioned above. Just getting on the plane and making the commitment to go back is the hardest thing. Next, was the deja vu experience while driving under the bridge and being received at the admin. building, while being overwhelmed by old memories of having crossed for your final trip last summer. It was an obvious reminder of how you'll be repeating a lot of activities you no longer desired to. However, after you get picked up again it seems to blow by. Plus, you have the motivation that is ever-present: This will be your LAST time here. I may be an ass for saying this (hey, it's my style), but it was nice to see others get dropped during the training cycle. This wasn't because I liked seeing it, but because there were those that had no business leading other Marines. It felt good to see the system work and know that those who were unfit for the job were going home. (I'm referring to leadership/attitude/lazy problems.) Nevertheless, this system is imperfect.
If I would have never spent any time enlisted, I doubt I would have known how important it was to have competent leaders taking a commission. I tried to keep that in mind, along with the idea of how much it would suck having to go home with my tail stuck between my legs, while explaining my reasoning for not making it through something from start to finish. Those thoughts were of no concern to me when I went in enlisted after high school.
BTW, I know I'm going to catch hell for this.... I went through Navy boot camp prior to graduating Marine OCS. There was very little comparison between the two, other than the language and general military knowledge. Despite that little smudge on my record, I didn't fare so bad while in Quantico. But, I believe it would be difficult to replicate the feeling of being a teenager fresh out of high school, first time away from home, and having taken on 4 years of a totally different life (at which time you were convinced that your entire enlistment would be like boot) away from everything you know while at OCS. The experiences, to me, were uniquely different.