Although I understand the appeal of this anime, which made me stick with it for 150-odd episodes, I just couldn't be bothered after many weeks of watching. After all, how many times can you watch one guy stab someone in the shoulder without getting bored? The answer: 156 times.
Season 1: Ichigo (strawberry, he he...) is a 15 year old boy who can see spirits, and one day he and his family is attacked by a giant monster thing, called a Hollow. He meets Kuchiki Rukia, a shinigami (death god, basically a grim reaper with a massive sword instead of a scythe), who transferrs her powers to Ichigo so he can defeat the hollow and save his family. Much hilarity ensues when he is unable to give the powers back, and Rukia is little more than an ordinary spirit.Eventually, they get this annoying modified soul thing called Kon, which is one of the most annoying anime-related things ever, almost as annoying as that girl's laugh from Ouran High School Host Club, who spends most of his time being annoying. The Quinceys and Uryuu are introduced, who are actually pretty cool. Ichigo's annoying ginger friend possible non-love-interest Orihime is introduced, but I don't think anyone really likes her. There's some big battle, then the season ends with a guy who looks like a pineapple and Rukia's brother, Kuchiki Byakuya coming to take Rukia back to the Soul Society (the afterlife). Ichigo gets his ass thoroughly kicked, and Rukia goes back with her brother.
I enjoyed this season, if only because it was fresh and I enjoyed the frequent fighting, as well as the concept of Shinigami. At this point, Rukia and Ichigo are still sort of funny, Ichigo's continued partial uselessness is still amusing, and other minor characters are still minor.
Season 2/3: They decide to get Rukia back, so there is this really annoying series of battles which are infuriatingly non-chronological, so you'll have one episode of Ichigo fighting someone, nearly defeating them, then the episode ends, but the next episode will have Uryuu fighting someone, nearly defeating them, then the next episode will be back to Ichigo. The pineapple guy, Renji, becomes a good guy, and they rescue Rukia but not before there is some annoying battle between Ichigo and Byakuya Kuchiki, but before they can actually rescue Rukia there's some random setbacks, long story short, some minor character called Aizen turns out to be the major baddie of the show. Renji and Ichigo both fight Byakuya, who has the girliest attack ever. Ichigo's bankai (more powerful attack) somehow defies the matter conservation of the universe and changes his outfit and sword, making his outfit more pretentious and making him much faster.
I was starting to tire during this season with the constant fighting, Orihime being useless, Sado saying nothing, Uryuu being emo, Ichigo trying to be manly and getting stabbed in the shoulders a lot, and Byakuya turning out to have the lamest-looking attack ever. It was okay, not brilliant, but okay.
Season 4: It's like a fanfiction, but written by actual writers! This season is totally pointless, and you can just skip over it and not actually miss anything. Seriously. I wish I hadn't watched it, it's really boring and stupid.
Season 5: At some point, Orihime is kidnapped by Aizen's henchmen. Renji, Ichigo and Uryuu decide to go and rescue her, bla bla. This is about where I got bored and stopped watching.