"Problem areas" are bullshit. Here's why:
There's nothing inherently unhealthy about having full hips, thick thighs, squishy upper arms, cellulite (which is actually considered a secondary sex characteristic, like boobs or an adams apple!), a soft belly, laugh lines, or stretch marks. A perfectly healthy and fit person can have all of these things. They don't hinder a person's ability to function or enjoy life.
So why do we hate and fear them so much?
The more (perfectly normal) parts of our bodies we feel insecure about, the more products we'll buy trying to "fix" them. A perfect example of this is back in the early 1900s when the Gilette company wanted to start selling to women in order to make more money. So they created an ad campaign that showed female body hair as being unattractive. And all of a sudden, female body hair was a problem. A problem that could be fixed... by buying a Gilette razor.
And the same stuff is still happening now. Just imagine how many companies would go out of business if we all decided to stop literally buying into this "problem area" idea... All the pills, the creams, the plastic surgeries, the diet books, the diet foods, etc... If we all saw these parts of our bodies as normal instead of something to be fixed, all these multibillion-dollar companies would cease to exist. Which also means that loving our bodies is a big money saver.
Of course I'm all for supporting people in achieving their personal goals. If you want to build muscle in a certain area or get laser hair removal or wear a full face of makeup everyday there's nothing wrong with any of those things. Your body is your own, and you deserve to use and modify it however you like. My problem is with messages that try to convince everyone that they shouldn't have body hair/wrinkles/thick thighs/etc. just so companies can make more money. The whole "problem area" phenomena is just one giant meaningless marketing ploy. Your body is your body and therefore it's awesome just as it is.
And for some extra body-positive inspiration, here's a really cute video of a group of diverse female athletes celebrating their beauty and modeling together: