Peachespig's Rule of Entitlement
The first entry in a series that sucked was always the first one after you, whoever you are, got way too emotionally invested in an unreasonable outcome. Always.

Created by peachespig, modified and reposted with permission.

EDIT: Velvet_mace rephrased it better than I did.

Canon starts getting sucky the installment after fans get way too emotionally invested in an unreasonable outcome.