I am only neurotic about a 4.0 because it means more opportunities for law school admissions (especially scholarship money) and I’m extremely debt averse and the legal market is very not-great but I cannot imagine my Computer Science/Engineering/English/Education major friends being as obsessive as I am about it before for them, their respective career goals don’t require it so they can devote their time to more meaningful pursuits (internships, research, etc.)
Because for them*
It’s working smarter, not harder. If the end result’s still the same (or better) and you expend less effort, then why go through the trouble? If I having a burning desire to learn the material (I’m taking an extremely difficult class next semester on the meta-theory of logic, w/ natural, propositional, modal, and first-order logic because I want to, even though it’s hard), I’ll talk the class; otherwise, I’d rather take the professor who gives more A’s over the one who doesn’t.
- I decided to major in physics because I wanted to learn physics... It just so happens that when you really love the subjects you're studying, you tend to do well. I graduated with a 4.0 and that helped me get into some pretty top-notch grad schools. Other than that, I wouldn't say it has effected my life at all. Getting a 4.0 is not important - taking all of the hard classes, enjoying what you're studying, and learning the material are what's important. The good grades will follow naturally.
- It bothers me when people say, "Wow you graduated with a 4.0 in physics? You must be really smart. You probably didn't even have to work." I'm not any smarter than the average person. Heck, I didn't even have a 4.0 in high school and didn't do so great on the ACT... I struggled as much as anyone else and worked my ass off because I love physics. Please don't insult my hard work by assuming that I'm some sort of genius that doesn't even have to attend classes but still aces graduate quantum mechanics (they exist).
I’m a double major in physics and math, and although I don’t have a 4.0 anymore, I still have a 3.93. I get the same comments. “I wish math would just come to me like it does to you,”…no, it doesn’t just “come to me.” I study my ass off to do well in my classes. “It must be nice to just get physics!”…No. I study my ass off. Sometimes I am thoroughly confused about something until I take the time to break it down and really analyze it.
“It’s working smarter, not harder”
I think it can quite easily be argued that taking classes multiple times is not the ‘smarter’ way to work.
I think any college student student knows that getting a 4.0 all throughout college is actually not entirely in your hands. As has been mentioned, the grade in some of your classes depends on the TA that grades and if they’re harsh or not. For example, I got a grade on a midterm that I felt was unreasonable. I took my midterm to a different TA, and after they checked my work, they saw the first TA graded unfairly and that I actually answered some of the questions correctly. Raised my grade 5%. That may not seem like much, but the point is, is that subjectivity is a pain especially when it comes to TA’s that are inexperienced undergraduates like yourself. That’s why I’m an Econ/Math double major. MOST every class I take has a definitive answer; there is no room for a TA to grade harshly. Choose your classes based on the TA for that class, if you have that information beforehand.
it’s a good grade!
Most difficult thing in trying to get a good grade? ALL THE HARDWORK 
but of course they’re all worth it