Why do I lose interest instantly after starting a task?

ADHD brains are highly sensitive to novelty. The anticipation of starting often provides more dopamine than the task itself. Once novelty fades, stimulation drops, and interest can disappear suddenly. This is not laziness or lack of follow through. It is a reward system that turns down quickly. Tasks that include variety, visible progress, or external accountability are easier to sustain than those that are repetitive or vague.