My best LoTW surprise so far came this summer when I got a confirmation for Somalia, T5W, just about a decade after I worked it.
I just got a confirmation in LOTW for a YB station from 2003. :-) I have a few confirmations in LOTW that go all the way back to 1992. (Glad I put my paper logs into the database when I went to PC logging.)
I've been eligible for DXCC since the early 90s, but I never bothered applying for DXCC--until I hit 100 in LOTW. Applying via LOTW was extremely fast and easy. (Of course, now I still need to pull out about 80-90 countries on paper cards and send them in.) :-)