Inflation/deflation/reflation/stagflation, recession, bubble, boom/bust, growth/slowdown, breakout/crash, peak/bottom, euphoria/panic, recovery, austerity/stimulation, money printing/mopping up funds... I find all these phenomona and activities interesting. They are all manifestation of human desire and behavior, or the result thereof.
Then I also find cycle study fascinating. I was at one time an ardent student of this arcane subject, athough very briefly.
Different people combine cycle study with different theories, systems, techniques, or apply to it with different set of data, and come up with very different conclusions of what's going to happen to the economy, stock market, and even way of life, society, and the world at large, in near and very distant future. It's an imprecise science with lots of room for further exploration.