How on earth can anyone know what someone else's best is?
Maybe you're projecting your idea of best on to them. I used to think everyone was smart but that some of them were slackers like myself at the time.
In basic training I found out that there really are slow learning people. There were people without coordination. There were people who couldn't run as fast as I could. There were actually people who weren't that smart.
I always try and be the best at whatever I do but some people can't match my best no matter how hard they try. How fair would it be if I held everyone at my standard?
Although it might make you feel better about your own training, don't put your level of intensity, devotion or whatever on others. It just makes you look like a dojo snob!