Expressing degree

When you ask a question with how, you would usually ask:

- How? (for adjectives and adverbs):
"how bad…?"
"how comfortable…?"
"how fast…?"

- How much? (for verbs):
"How much do you know…?"
"How much does he want…?"

- How much of? (for nouns):
"How much of a businessman is he?"
"Not much of one."

- To what degree? / To what extent? (for verbs) :
"To what extent do you believe him?"

- How far? (applied to verbs):
"How far do you agree with me?"
"I agree with you absolutely."

We use these words to indicate degrees on a scale from minimum to maximum, be it size, darkness, wealth, etc. So, we have different positions on that scale and we use different scale words with
(a) adjectives
(b) adverbs:

i) Indicating extreme position on the scale

(a) very:
“He’s very friendly.”

(b) much, a lot (informal) a great deal (formal):
“It hurts very much.”

ii) Intensifying the meaning slightly

(a) quite, rather, fairly; pretty (informal) ”It’s quite expensive. “He was rather annoyed.”

(b) considerably, rather; quite a lot (informal) “Prices have increased considerably.”
“I rather like him.”

iii) Toning down or decreasing the effect of the scale word

(a) a bit, a little, slightly (informal):
”It’s slightly uncomfortable.”

(b) a bit, a little slightly (informal):
“Prices have fallen slightly.”
“I know him a little.”