Anime - The World God Only Knows

The World God Only Knows
2010 - 2013
36 Episodes at around 25 minutes a piece

Plot:
Keima Katsuragi a 17 year old boy that is an avid gamer rejects reality and lives solely for Dating-Sims has earned the nickname "God of Conquests." His nickname comes from the devotion of playing nothing but dating simulation games and easily beating them all within a short time span. In a twist he finds a magically collar around his neck that will end his life if he doesn't assist his partner in capturing "loose" souls from hell using his gaming skills.
He has to fill the emptiness in a target's heart and then with a kiss draw out the souls from his targets...

Commentary:
All of the targets except for a couple are all high school girls, and Keima literally "conquers" all of his target via dating-simulation theme motifs. Keima isn't really even in the chase for goal of the heart he manipulates but to retrieve the souls inhabiting his target. Luckily for him once he completes his task, the targets forget him and everything leading up to the kiss.
So basically Keima is one of the biggest womanizers in history, right? Not exactly. Keima does NOT go anywhere further than a kiss and half the times the kisses are forced by the target, and not initiated by him at all. For all he cares about is getting the contract done and going back to playing his dating-sims. Though it would appear there's a lot of souls to extract and collect the first 24 episodes focus on how Keima fullfills his goals and between these moments parodies of other series can be seen. One of the biggest ones is the gamer idea, of course.
Eventually on the 3rd season the mythos behind the "loose" souls and demons is further explained and Keima has a different mission. Somewhere in the girls he's conquered are six Goddesses that saved heaven and Earth from calamity. Keima's only clue is that each host for the goddess recalls the conquest from prior season(s), and in order to awaken the Goddesses he has to fill the hearts of girls once more to revive the power of the Goddesses.
Here's where the drama starts to play, as Keima has a limited amount of time to do this, and he can't let each host know what he's attempting to do. This creates some tension that plays on each of the hosts and Keima himself.
Once the story arc ends through the laughter, the tension, and experience you can't really hate Keima, instead you sort of feel sorry for him.
I say the story arc ends as the manga is still on going, and at the last episode you still see the magical ring around Keima's neck - meaning this is just the beginning of his journey.

Note: there 3 or 4 OVAs after Season 2 that fill in some story before the start of Season 3 as the Goddess story line really takes off after one or two episodes and cameos from additional characters not seen in season 2.

After finishing the series and looking back on the development of Keima from episode 1 to 36, there is significant growth. Even the conquests have some character growth as well that serve to capture part of the period known as high school. Yes there's a bigger story behind this, but the bigger story (the Goddesses) pair well with the drama of high school and sort of serve as a compliment to breaking up both sides. A little drama to lax the seriousness of the story. A little seriousness to emphasis a bit more on life and the big picture.
One thing though, is that Keima does paint a sort of horrible picture of making hearts and emotions as tools that have no real repercussions in life. But this is one of those things that, like all good fiction, is an element that is suspended.

I'd definitely recommend this series if you're looking for something cute, fun, and not too heavily serious.