What is the meaning of 'quite'?

What does "yet that mean" mean?

"Yet that mean" here simply means "but that unkind" driver. He is comparing the "kindness" of "Darrel" to the "meanness" or unkindness of the "Buddy driver". The word "mean" has a few meanings in English. In this case, it is being used as an adjective to mean that someone is unkind or unpleasant. Ex: Stop being so mean to me! Ex: She just said it to be mean. "Yet" is being used as a conjunction and conveying a meaning similar to "but" and "that" is just being used as a pronoun to identify the person other than Darrel. Ex: I told you not to yet you still did it. Ex: You look so tired yet you have a lot of energy. That's amazing.

What is the meaning of "condition" here?

"Condition" in this context refers to having a medical problem. She is saying, somewhat humorously, that she has a medical problem (condition) where she starts panicking when she thinks about dating.

What is late-night snack?

"Late-night snack" is a snack that is eaten before going to bed or during the late night. Synonyms are "bedtime snack" or "midnight snack". Ex: My favourite late-night snack is a hot brownie with a vanilla ice-cream on top. Ex: Having a late-night snack could destroy your diet.

What does "ever" mean and how do you use it?

"Ever" is an adverb meaning at at any time, at all times, or always. It is used in conjunction with a verb to modify (or describe) it. You can use it in negatives, but it is more common to use "never" in such contexts. Ex. I won't ever eat meat again, I'm turning vegan. Ex. I have not ever eaten fish in my life. -> I have never eaten fish in my life.

Why'd he say "have seen the girl" instead of "saw the girl?"

Good question! "Saw the girl," which is past-simple tense, would imply that he saw her a while ago, while they were not in the same room, or at a previous moment. But since they're still in the present moment, the present perfect tense is used. "Have seen the girl" also implies that he has already fully acknowledged and noticed her presence in the space, so the action is already complete. Ex: I've just won the game. => Present perfect tense - which implies that it was very recent Ex: I won the game at the fair. => Past-simple - the time of winning is not clear