Short: On the surface, Moteki is a hilarious comedy about a virgin loser trying to get with women. A little deeper, it's an honest and raw story about discovering oneself and finding happiness.
Longer: I've read three of Kubo-sensei's works: Again!!, Moteki, and 3.3.7 Byooshi, and they're all fantastic. She really likes main characters who fit the "loser" stereotype in one way or another. In 3.3.7 Byooshi, it's a country hick in the big city. In Again!!, it's a loner. And here in Moteki, it's virgin* loser Fuji who has no self-confidence.
It's hard to talk about Moteki without bringing up Welcome to the NHK, another redemption
story about a loser, and one of my favorite series. Like Satou from NHK, Fuji is an amazingly flawed character who constantly messes things up, and constantly thinks of how other people see him. Listening to his internal debates and thoughts is a real treat, especially when all of the other characters are so flawed too. It becomes this wonderful mess of misunderstandings where Fuji can't tell what's going on because he's thinking of only himself, but the other person isn't much better.
I think that anybody could appreciate some of what makes Fuji tick, even if they might not be in his shoes. His path to building self-confidence is frustratingly slow and painful, but in some sense it feels more real than any other manga I've read.
* not really a virgin