I have a couple.
The Grateful Dead are my big one. None of my friends like them and I live with someone who hates their music so much I'm forbidden from blasting it from the stereo when she's home. I didn't like them for most of my life, and then something just clicked when I heard them live a few years ago.
Jerry Garcia was a genius and one of the best guitar players to ever live. That said, I can understand why people dislike them. Most of their studio albums have them playing the bare minimum of their potential. Casey Jones sounded better played live than it does on the radio. The Dead have such a massive archive of live shows, you have to really dig in to find what you're looking for. Besides that, I think they are also a musician's band. If you play music, you have more of an appreciation for them and how they were able to endlessly jam (then again, a lot of guitar players on the internet seem to really hate Jerry for some reason).
I like their 1970-1972 period the most. They sound like a mixture of Blues, 50s Rock, Country, Folk and Americana all rolled together.
Europe '72 is really the only Dead album worth checking out to know if you want to give them a shot. Don't go by what you heard on the radio, this album is the litmus test if you want to dig into their music or not.
For all their live shows, if I had to recommend just one, the Hollywood Palladium show from August 6th 1971 is my pick. Jerry played a Les Paul on that show and sounds heavier than he usually does. There's a blistering version of Bertha and Casey Jones, and the best version of Brokedown Palace with a slow blues solo.