I over steep. I under steep. I reuse a mug for different teas without thoroughly rinsing it out - sometimes I haven't even finished the prior tea. I let the tea get cold. I burn my mouth. I only use tea timers when tasting a new tea. After that, I usually forget altogether. Perfection is not a requirement for a cup of tea - it's just a lofty goal. Tea should not be a mystery that requires a guru to solve.