Hi @Mimi95
Nice to meet you and welcome to the Forums. I used to suffer the same anxieties as you do about rather similar situations. Its all about thinking of these situations in a new way, take for example going shopping, remember you are the shopper and they want your money, so generally they will always try and please you to get that money from you.
Lets say the motorist yells at you, its not you he is yelling at, its probably some incident in his own life that he is yelling at and it has nothing to do with you.
Reverse parking, i'm a crap parker so if ever I attempt a parrallel park, I always make sure that the space is plenty big enough and if I can go forward in, I will always do that.
If someone yells at you on the phone, I would always let them yell to their hearts content and say nothing, and then continue to say nothing, they will invaribly say 'hello, are you still there' to which i would reply 'just waiting to see if you have finished' if they yell again, i would let them yell -- eventually they would always calm down.
So dealing with stressy situations, its all about looking at them in different ways.....Asgard