This question is mainly for all those that are not speaking English as their first language.
For me there has been some words that are difficult to pronounce correctly. Maybe saying word aloud gives you a feeling that you're doing something wrong.
It would be interesting to know which words you find difficult?
My favourites are squirrel, miscellaneous (plus I have to always check how is this written correctly) and murderer (it's mumbling when I say it)