The first and most important effect of your GPA is how you feel about yourself and your academic performance. If you don't achieve the goal you set for yourself, it can cause doubts and anxiety. When you are in the process of deciding on the GPA you want, be realistic. If you are now at a 3.0 GPA, aim for 3.5 and work your way up.
Employers are looking for people with communication and analytical skills and who are flexible and want to learn. Although having a high GPA won't necessarily get you short-listed, it is still a good thing to have on your resume, and if the decision is between you and another candidate, your high GPA could work in your favor.
According to the UW-Milwaukee, most graduate programs require a GPA of at least a B average, whereas you can get a bachelor's degree with a C standing. The stiffer the competition for the graduate places, the more emphasis the graduate school places on your GPA.
If you are applying for scholarships, your GPA is very important as it will affect whether your application makes it into the "to be considered' pile. Scholarships are generally awarded to students with the best marks, although there may be other considerations such as financial need, age or gender. Regardless, the higher the GPA the more likely you are to be able to get financial assistance.