I find all angling methods interesting - I just enjoy fly fishing most of all. Some of the best and most knowledgeable fly fishermen I knew in the UK started out their fishing careers as Coarse fishermen (coarse fishing in the UK is pursuit of any freshwater fish other than salmonids). These guys really knew their watercraft so the transition to fly fishing was relatively easy for them.
Likewise with bait and spin fishermen in saltwater - which is how I used to fish. Early in the season I enjoy stopping off at the big ditch on my way to the Cape to watch the guys live lining herring.
I own a spinning rod and generally pack it when I'm going to a new location. Throwing surface plugs out over a deep channel down in the Caribbean can be a whole lot of fun - you just never know what's going to come up for a look!
What does or doesn't constitute fly fishing is a debate that's been going on since before the last century and will probably (I sincerely hope) still be going on well into the next.