Three things you must through your thick skull before you fight a Vayne.
#1 - She is a hyperscaling monster that will demolish almost any target in a straight up 1v1.
Most people know this but many of them decide to ignore it and fight her anyway.
#2 - She heavily relies on stealth. Upgraded Sweeper is her worst enemy.
If you decide you really need that Yellow trinket tho, at least upgrade it to a Pink Ward ffs.
Or have some form of true sight, such as Tempes/Cripple.
#3 - Running away will only get you killed.
If you are already fighting, don't try to run away. It will only make her job easier.
Yes, Vayne is super annoying when Strong, but there is always something you can do to deal with her.
Most champions can actually fight her in the mid game, however, most players are afraid of something they can't see.
