1, if you really like something so much that you use that almost everytime, you can say 애용하다.
In eng, you can say 'I love to use ~~'. I think there is no word translated exactly the same as '애용하다'
2, 더라고요 is like 'I think ~~', 'I guess ~~'... etc.
3, in conversation, meaning is the same.
4, are you mad at me??
Can I ask you a question??
I want to know the difference between 'mad', 'angry'.