I love the Bleach anime/manga,but it REALLY bugs me that pairings that actually make sense are ignored/disliked,while the awful ones are well supported,despite either a lack of evidence on one or both sides or it being outright stated that a relationship is "not romance"...
Ichigo X Rukia....NO...just no...I don't care what the (completely heartless) idiots at Studio Pierrot try,they aren't a couple,nor should they be...
What makes their relationship interesting is that it's NOT romantic,it's one of the reasons I got into the series in the first place....To top it off,Kubo's even SAID they don't have romantic interest in one another (and,if I remeraber correctly,it was in an interview about the third movie,Fade to Black,so no,that movie doesn't prove your ship is right)...
Ulquiorra X Orihime...I don't find Stockholm or Lima Syndrome very romantic,in fact they're both kinda creepy...Plus,there's the fact that Ulquiorra's a major jerk to her (I wouldn't be at all surprised if most Ulquihime "fans" actually ship it because they hate Orihime),and that Orihime is in love with Ichigo (whether or not he reciprocates doesn't matter,the fact remains that he's the one she loves)...
Kaien X Rukia...Sigh..where to begin....OK,first off Kaien was MARRIED,and seemed to be completely devoted to his wife,Miyako,and second Rukia was NOT in love with him,he was more a mentor/big brother figure (someone who was looking out for her,like Byakuya should have been)...it bothers me when people confuse platonic and romantic love...
Uryu X Orihime....While I don't hate this one QUITE as much as the others mentioned(since there's a bit of canon evidence to back up Uryu's feelings),I'm still not fond of it...I'm sick of people treating it as reciprocated and canon..it's not(Orihime has no clue about his feelings,and thinks he likes Rukia..plus,Uryu seems to be pretty well aware of her love for Ichigo)...
Yaoi/yuri with straight characters....I'm not particularly fond of either, I'm OK with it if the characters actually are gay,but in most cases of fanmade pairings,either one or both merabers of the couple are actually straight,so no,it's never going to happen in the actual series...