Optimize why? So that we can spend the extra seconds on our social media apps? People need to learn to slow down and not try to save twenty seconds when boiling water.
Why should I optimize my code? To save 420ms for what?
I dunno. I try to optimize everything in life, maybe it's the engineer in me (I find it fun and interesting how people do things inefficiently). I also try and measure ingredients exactly (e.g. 420g of flour, not 419g or 421g), however that might be some low form of OCD. /shrug
Whether I use that extra time or not doesn't really matter for me.
No, boiling water in the kettle literally saves you 10 minutes of hanging around every single time you cook, it's a no brainier.
Anecdotally, with two young children (5, 1), the savings add up and mean twenty more seconds with them or not being overwhelmed after they're asleep with the state of the house.