[RelativeDelta]

Somewhat. It's a novelty factor response. If you're not used to hearing background noise then every little thing sort of 'pops'. Individual key clicks sound more distinct, you pay more attention to the sound of footsteps etc.

It's just your brain being unaccustomed to the sounds and reintroducing them.

[politelemon]

Could it be similar to the return to office effect some people are noticing. After a year or more of working from home quietly, many who return to a noisy office are struggling to focus and are wondering how they ever got work done in the past!