I think we all have that feeling in us, i remember when i was on exam(i didn't nervous tho) and then i needed to ask for another paper for my esse, and i kew that i just couldn't say, that was so stupid, it took me about 1 or 2 minutes to get confidence and say it (yes i know, this is very stupid but I couldn't help it) i was afraid that the people of my class would start to laugh at (despite the fact it's exam) but in the end i said it almost perfect and no one noticed anything wrong on my speech (i guess) The second case which i remember so clear so my parents told me to go to pharmacy and buy some kind of drug for heart (and after i heard this phrase i was already like (damn i will stutter, I'm sure i will, no i don't wanna do this, this will be so embarrassing) and i just said "ok" cause you know there is no way to refuse, and after trip to pharmacy all my thoughts were like (you just need to say a few words, don't fail it, it's not that hard, you can do this) and what do you happened? Yes, i stuttered when i bought a drug i said thank you, AND I SWEAR THAT WAS THE HARDEST THANK YOU IN MY LIFE i tried to say this word for about 5 seconds, 5 SECONDS! then i just calmed down, did a deep breath and said thank you without stuttering, and after i left a shop, i felt so so soooo bad, i blamed myself, i hated myself, i was so angry with myself, i think i was that angry, that i could have lift up Everest, so that is my story, indeed this thing literally controls our lifes