This is a perspective from 26 years down the road:
The money you actually get deposited into your bank account each month is enough to live comfortably at that stage in your life. As a JO, you should only have minimal dependents and costs associated with.
The money you actually received increases each year by the January percentage, by the chart each time you increase service time by two years, and each time you advance.
The money you actually receive and can spend is not decreased by a student loan payment or health insurance (but dental insurance for dependents is a premium-based insurance).
The money you actually receive for housing allowance is tax free.
Let's talk about the non-monetary things your civilian peers will not have:
Will everyone from College U have a job after graduation? Each graduate of a SA will have a job at the same base pay, only the view outside the window is different depending upon the assignment pecking order.
An opportunity to advance in the organization throughout your career with increases in pay. Can someone starting at Corporation XYZ see their path clearly up the ladder? Can almost everyone starting at the bottom move up who has the right abilities?
Job security. As long as you do your job right and to the best of your abilities, you should be able to keep that job at least 20 years. Can Corporation XYZ offer you that guarantee?
Health insurance coverage. Yes, it's free or almost free (some areas you might have to pay a co-pay in order to see the doc of your choice outside a military base). Can your civilian peer find a job with no health insurance premiums during some of the most expensive years of their family lives? Birthing babies, well-baby check ups, ear infections, vaccinations, etc.
Opportunity for advanced degrees. Most services offer members full pay and tuition while earning advanced degrees. Will Corporation XYZ give someone 2 years off with full pay, pay tuition expenses, while your civilian friend works on a master's degree?
Let's not forget that lovely lifetime check that will arrive each and every month for the rest of your life if you are able to give 20 years to this organization. What will your civilian peer be doing at age 50, 60, or 70 for guaranteed income. There's also the access to health insurance for the rest of your life.
The grass will always be greener, and the depth of that color depends upon the economy. Right now, civilians are looking at their military counterparts thinking a little bit of sacrifice and risk aren't so bad for security. When the economy is good, the money sirens will call out that civilian life is the land of gold-until the bottom drops again.
Go into a branch because you want to serve, because you find purpose in the mission. Find security in the fact that if you live within your means, you will be able to save money, have a comfortable life while serving, and a comfortable life with a second career and the lifetime check.