My dad hates snot.
Not actual snot but the word "snot". You can say sh*t, b*tch, f*ck around my Dad and he will likely not raise an eyebrow. God help you if you use "snot" within ear-shot of him. The context and usage appears to be important....
"You have some snot running from your nose"
This appears to be fine with dear-ole-Dad. I guess using "snot" to refer to snot is ok.
"Quit being a snot"
This will get you a daddyslap to the back of the head. Using the word "snot" for something other than mucus is where the trouble apparently begins.
Oh... and before I forget (in the off-chance you run into Dad today) all the above holds true for "booger" too.