Understanding Employee Benefits and Taxes at 29

I finally understand how benefits and taxes it by applying my coupon deciphering skills.

Before: I thought if you made 40k, you were in the 22% tax bracket; the whole thing. Look at the chart below from forbes.com
I finally read today on nerdwallet.com that your whole salary/income gets distributed throughout the tax rates. For example, lets use a salary of 40k/year.

10% - $9,525
12% - $29,175
22% - $1,300
===$40,000

Now, this is where your pre-tax options kick in. See the $1,300? It's taxed at 22%. But let's say you're going to get braces and you plan to pay $1,300 toward it. Instead of just calling it a day with you benefits after doing the math, if you have a flexible spending account (FSA), you can put that $1,300 in there and now it won't get taxed 22%, which is $286 you would've paid toward taxes. But because you're telling the government you're going to use it toward ortho, the government is not going to make you pay $286.

Something to think about as you get older and have kids and all is your health. There's a high deductible health plan (HDHP) that you could pay $16/month or $44/month for one that's lower deductible since you're paying more per month.

The total so far is 26 paychecks * $16 = $416
and the low deductible is 26 paychecks *44 = $1,144

The difference between the two is $728/year. Now the question is: A) Do you want to save $728 and tell yourself you shouldn't go to the hospital unless it's a real emergency or B) Pay the $728 more and be at peace if you have any health concerns.

What's easier to control, your health or your money? You can't predict what can happen, so for the $728 difference, I am going to pay it to be at peace.

This is just the short and simple version. I hope this helps anyone that's confused like me. Everyone's situation is different, so ask your human resource about everything you're unsure of. Happy adulting!