Some interesting questions and answers:
Why is accuracy not the best measure for assessing classification models?
Are unbalanced datasets problematic, and (how) does oversampling (purport to) help?
When is unbalanced data really a problem in Machine Learning?
Is accuracy an improper scoring rule in a binary classification setting?
Is my model any good, based on the diagnostic metric ($R^2$ / AUC/ accuracy/ RMSE etc.) value?