Let me start by saying that I know very little about classical music outside of the big names, and their major works. I'm not sure why I never took more time to learn about it.
Today, I caught a good friend sitting near a pond at my school listening to "Soave Sia Il Vento" from Mozart's opera "Cosi Fan Tutte." I wasn't going to disturb her, but she invited me to listen along with her. Honestly, I've never been more entranced by something (We listened to some more music, but I didn't dare break the silence to ask what each song was). After I finished classes I had work soon after, but when I got home I started combing the internet for classical music, and opera (I've actually become quite fond of opera pieces like "Habanera"). After maybe an hour of doing some reading and compiling an OK list of music I realized I hadn't even begun to scratch the surface. I'm here asking you wonderful human beings to give me literally all of the recommendations you possibly can, and maybe some resources on where to really learn more about the music. Anything you like, love, or feel is a necessity I want it. I think next semester I'm going to try to take a class focused on classical music or opera(Not to perform, but to learn the history and stuff).
EDIT: Ok so I have a 50 hour 17 minute long playlist. I'm gonna work my way through this over the next month or so. I want it to be a gradual process rather than just listening to one after another. I'm gonna report back in a month or so about my experience, the research I've done, and what I learned along the way.