Feeling Stronger After Deadlift?

Why when I do deadlift, I feel stronger after doing an heavy set ? I always notice that when I load/unload the bar. When unloading, the plates feel MUCH lighter than when I loaded the bar. Is that common?

Warming up your muscles maybe?

I notice the same thing. I think it’s kind of psychological. After lifting a couple hundred pounds a bunch of times, what are those dinky little 45 pound things anyhow?