Singing is all about the emotion behind it

Well, at least 50% of it is. Maybe you won't get on American Idol for emotion though, but it's definitely something that can be learned. And when learned from coming from an average level, it can be appreciated extra. There is no harm in singing to yourself, or friends, especially if you're uncomfortable with your skill level. Heck, it deepens your relationship with yourself and others the more you suck at it yet are willing to sing!
As for "you are GOOD at but hate", I am a pretty good sketcher, but I really dislike it. It's what I was known for in highschool, despite that I only used it to get silent attention.. People waling by with compliments. I remember once I drew something just to get the attention of a girl the day before she graduated. I had never spoken to her before, but it worked. She came by the day after I drew it, while I took it out, and talked/complimented me... I guess sketching meant something to me in the end, still never enjoyed it....