I love the lightbulb of connection and discovery. Nassim Taleb says in his book Antifragile -
"...the simpler and more obvious the discovery, the less equipped we are to figure it out by complicated methods. The key is that the significant can only be revealed by practice. How many of these simple, trivially simple heuristics [i.e. wheels on a suitcase] are currently looking and laughing at us?"