I went through a phase last year of really liking Formula 1, yet when the new season starts I'm not sure if I'll watch any of it. Maybe it was just the excitement of discovering something new that held my attention (as well as the crashes!); maybe I cared more about the strategy then than I do now... not really sure.
Loads of Olympic events I go nuts for. Sit me in a room with some obscure sport that I've never heard of - especially with the Winter Olympics - and by the end of the day, I'll be so caught up in it, you could have me commentating and everything! Also, tennis I enjoy watching, but it can become kinda same-y if you watch a whole match.