I liked them before they became popular
A person says this when a band they supported for years becomes famous. They’re annoyed because they had to put up with the band before they were cool, and now everyone else gets to enjoy them.
I had to put up with them before they were cool, and now I’m the only one who still likes them.
I was stuck with them before they were famous, and now I’m the only one who still remembers.
I was the only one who knew they were going to be famous, and now I’m the only one who still likes them.