The What Are You Missing mod for Stardew Valley gives you a comparison of what you have to what you could have in the current season. It then shows you what you are missing. 

The basic idea of the mod is that it shows you what you are missing in the current season. 

The first reason why I created this mod is to help me complete the community center in the first year. I wanted to have a way to know where everything was so that I would never get lost.

The second reason is to reduce the number of times that I had to go look something up on the wiki. If you want to know about any of the latest events or find information about how to play the game, then you need to look up on the wiki. But sometimes, it is hard to find the correct information, and I wanted to have a way to avoid that.