I have a 60hz right next to my 144hz and it doesn't bother me at all. It's just text, 99.99% of the time it doesn't move.
But dropping down to 1080p or a smaller monitor is instantly noticeable and very very unpleasant. Everything just looks so fuzzy and hard to read.
The hedonic treadmill is getting brutal. Going up to a 4k/34" monitor was nice but it quickly became normal. The main effect was how bad it made 1440p/27" monitors!