Most of people would learn a new language by TV dramas, movies and songs.
But the case is different in Cantonese.
Actually, Cantonese has got two versions: spoken Cantonese(口語) and written Cantonese(書面語).
Spoken Cantonese is the Cantonese we speak everyday, but it seldom exists in TV dramas, movies and most of the songs. (Only a few local words which can't be translated into written Cantonese would be type for subtitles directly.)
Written Cantonese is based on standard Chinese, which reflects people from mainland China and Taiwan can understand easily. It is different from the Cantonese we speak everyday, but it is used for most of dramas, movies and songs for the subtitles.
Therefore, if you want to learn Cantonese, please select correct platforms. Here are some suggestions.
1. www.lihkg.com 連登討論區: Most of the post and topics there are based on spoken Cantonese
2. Rap music: Please search some singers on Youtube, such as 農夫, their songs are based on spoken Cantonese.
If you are interested in learning Cantonese, please contact me.