Taking commands to the next level (without luring)

I feel like l'm going to struggle to explain myself here in a good way, but here it goes…

My struggle is understanding what it takes to get some commands nailed down to the point that just the word itself works. For example why is 'sit' and 'down' so easy compared to something a bit more advanced like 'side’ or ‘place’? I get that I somewhat answered my own question there by stating it's more advanced, but I just feel like I'm missing something when 'sit' and 'down' are picked up within a day or two while ‘side’ and ‘place’ have been a work in progress for months now. He does know the commands to some degree and will follow my hand and sit promptly to my side or to his place but if I try to just say "side" or “place”with no luring with my hand and a treat he will just sit or lie down like he's still unsure of what he's supposed to do.

Am I just being impatient and the simple answer is that some commands just take much longer? Or is there some steps I might be missing to help him better understand?