One very common find that stuck out to me the most was the rather ubiquitous distribution of leftover alcoholic beverages.
Above are 2 images of some wholly intact bottles I found. The most common finds were just the caps of these bottles, as well as beer cans. The most popular choices, based on the trash I found, seemed to be Corona and Bud Light.
Most of these were found around awnings and pavillions, where parties may have been held (I once even saw confetti under one pavillion). However, I also found them in rather random places; how did a whiskey bottle end up 3 trees deep into a forest? It must have been thrown there, but how and why?
My theory is, given that alcohol is known to be a depressant (not the one that makes you sad, the one that reduces stimulation - one can read more about how alcohol is a depressant here: About Alcohol), that those who drank were probably too relaxed to throw away their trash (properly) but had enough energy to scuttle their act by throwing it far enough into the forest that no one will find it, or simply leaving it where they last were.
Whatever the case may be, it is an undeniable fact that many alcoholic beverage bottles are left at the park - one can only speculate how they got there based on their surrounding context!