Do you feel compelled to tell people they are full of shit and you know it?

So, what I am really talking about is when you know someone is purposely doing something, maybe it is lying, or they send you on an errand to distract you, or purposely block you so you can’t get by, and then they try to act like they are doing nothing purposeful. Do you feel like you have to tell them that you know what they are up to? Or, do you just ignore it and brush it off? Or, maybe make a mental note, and remember for any future interactions, but say nothing?