If you're used to 60Hz and you've never seen better, you would be comfortable with it since your eyes are telling your brain that its ok. Its a psychological thing I guess, just like Plato's Cave

However, once you go higher, to say 75Hz or 85Hz, then you go back to 60Hz, you'd immediately be able to tell a difference. The recommended refresh rate nowadays is around 85Hz, but if your monitor can support even more, then go for it.