This will be a typical response, I suppose... I'm not very effective in short responses, and I take sooo long to finish a detailed one, but I do prefer the latter to make things clear in one post.......................................... *snap* Eh, Anyway!
*In some parts, I have felt that I am only citing the obvious, but... I guess it goes without saying that, following every explanation I made to a character is a "which lead me to liking her more <3".
Yuyuko=Patchouli
Yuyuko: I think because she seems to have a tragic past and now living a carefree-ish life. The first YuyuMyon doujin by CHRONOLOG led me to biting to art cuteness >w<. She has Youmu beside her (to tease on)... and Yukari on the far side (a friend of her past self)... then all the frills in her yukata-like outfit... On the other hand, my YoungestSis likes Youmu the most, so makes YuyuMyon as our default Touhou pairing :3.
Patchouli: being anemic but can cast oh-so powerful spells while wearing long, loose, nighttime-like outfit... I just tend to like someone who has Knowledge as a last name... or in other words, who is simply knowledgeable in...stuff because of reading. Oddly, Patchy with glasses isn't as much favorably for me.
*This is when I was only reading doujin comics and seeing a few fan art... A little tiring about favs because though I do like them, and besides the feeling that I've written this a few times (or so I thought), I'm still in the process of finding the reason why I actually liked them >.<...
*snap* Anyway! Then there was the discovery of Touhou itself...
Reimu=Marisa
I simply can't skip these two heroines.
Reimu: .................................... because she's the heroine? Because of her trusty intuition? Perhaps, but... not quite... (couldn't determine, and it's not the homing Danmaku... no, definitely not that.)
Marisa: Witch fetish |D (not of the pervy stuff, but I just like witches in general), and seeing that she's a nice uke for Reimu, despite seme-ish traits. (or maybe they're both seme... *shakes head*)
*Fanart extends my liking to them (but not "them" only as a pairing, gee o_o;)
... Though when I saw the events & the battle after I defeated Yuyuko, she went top again for making me cry so emotionally ;_;... This is also the part that I accepted that Yuyuko and other charas that my twin friend who introduced me to Touhou liked were actually foes and final bosses in the game.
Rinnosuke=Renko=Luna Child (of the Three Mischievous Fairies) > Reimu > Marisa
This is when I started reading CoLA and SaBND. ZUN's Touhou literature packs a punch of knowledge and food for thought, and it's where I get to know several more canon personalities and stuff, I say.
Rinnosuke: probably influenced by my YoungestSis. He brings a very Gensokyo-ish perspective to the outside-world stuff, and he's the only male able to encounter the rest of the cast in a daily-life setting. I wonder if pairing him to Patchy is a nice idea...
Renko: Astronomy & Physics, a live GPS who is tardy, short black hair, her plain fluffy-skirt black-white uniform, an outside-worlder (in Gensokyo's perspective, that is), Mary's uke... Sana influence added later on.
Luna Child: ... "Waaaah, cute fluffy fairies! >w< I wonder whom I'll like the most among the three." So genuinely, I thought I had to like one of them, which turns out to be Luna Child (I'd like calling her Lunako sometimes, referencing to the Famitsu name of Persona 3 Portable's heroine). I thought she's a nice sidetrack to my usual/apparent "knowledgeable person" liking when I read that Luna was "not the brightest among the three." Her usual gloomy-like face among the two who is usually seen smiling, her fluffy nightgown-ish outfit... Second, the Three Mischievous Fairies as a whole, they linger around the nature of Gensokyo, experiencing the incidents somehow indirectly, and dealing with it in their own little natural ways as fairies.
Reimu getting over my Reimu=Marisa equation: Reading the official novel & comic, this is where I got to know more about Reimu's selfish-y but <something to counter that selfish side of her...caring?>-y personality. Marisa's as well, but I gave way to Reimu, shamefully because she's the main heroine in Touhou (for me).
Then there were the various points during the past year that lead me to the following characters:
Moriya Shrine Family, Kanako>Sanae>Suwako: the thought having two Goddesses as her "parents", influenced by Moriya Shrine Family doujins especially [Personal Color] ones. Just seeing the trio together calms me. Yey Shrinemaiden Sanae for a blue counterpart of Shrinemaiden Reimu! xD "2nd Player Miko", like Letty-sama recorded, minus two words.
Aya: influenced by my YoungestSis. That single "-desu" suffix she said in Touhou fan anime made YoungestSis' Aya hate turn 180?... not that I hated Aya before. That maple leaf she's holding (that somehow represents Fall season, or the fall of dried leaves), her flight with her black crow wings (though everone is able to fly, I found myself liking Aya soaring through the skies...at least in my imagination and a few arts & videos)... She also has Momiji as assistant or subordinate. Tengukami influence added later on.
Mokou Keine as a pair: I grew up on Mokou as I played IN's Extra... What does that have to do with Keine?......... Weird, fluffy |D *shakes head* The thought that she's protecting a human, even thought she knows Mokou is an eternal being. What I'd like to point out too is that, my liking level for Mokou & Keine, with Wriggle & Mystia, is veeery far from the rest of the Eientei cast.
Marisa attains a position higher than Reimu: ...probably because of the several Marisa doujins, discovering that Marisa appeared in the 2nd PC-98 Touhou as a boss (regardless if that was the same Marisa of Windows or not), or just my witch fetish at work, ... or maybe because she's actually human, despite being all magician-related or something... I'm not sure myself, but eh, it's Marisa だぜ(da ze)! (...no, it's not of the "da ze" either...)
Lastly, there's these recent and quick changes of my favorites... not necessarily on top of my fav list but has temporarily occupied the "favorite of the season" slot and has influenced me to raise her in my fav list, if such list exists in me anyway:
Re:Sanae: [GP-KIDS]' and [Personal Color]'s Sanae doujin, & several fanarts... Contrast to GP-KIDS' doujin, I find Sanae as Reimu's younger sister sometimes. Her looks consisting of the colors blue-white (miko outfit) and green (long hair)... Also, Solais influence.
Momiji: Momiji's part on the Bad Apple PV, [Happy Flame Time]'s Cold Wind but Warm Winter, [ciaociao]'s Momiji, the 8-bit SDM in the Early Afternoon video, & a few fanarts)
Sakuya=Remilia >Patchouli >the rest of SDM: my ElderSis Saki's losing inspiration in drawing females, so she asked me for Sakuya stuff (because Sakuya had so far the nearest candidate to having her favorite back-wavy or Nobu-like hairstyle).
*The quick change is mostly because of what I read (doujin comics) or see (fan art) as usual.
I do not hate anyone among the vast number of Touhou cast, by the way.
F... four hours~ @.@ *faints*