Adding too much banana in banana cake can have some consequences on the final result of the cake. While bananas provide flavor and moisture to cakes, excess amounts can lead to some undesirable outcomes. First, adding excessive mashed bananas can make the batter overly wet and dense, resulting in a heavy texture rather than a fluffy one we typically desire in cakes. The excess moisture may also affect how evenly the cake bakes, potentially leading to an uncooked center or uneven rise. Finally, an overwhelming amount of bananas could overpower other flavors present in the cake so that they become less pronounced or even taste muted compared to what was intended with proper ratios. Therefore, it is important to follow recipes' recommended measurements for adding bananas or make necessary adjustments based on previous baking experiences while being cautious not to overdo it with this delightful fruit!