For as much as politicians address the “middle class,” you’d think it would be more clearly defined. There is little consensus on what middle class really means, but everyone certainly wants to be middle class: Nearly 70% of Americans consider themselves middle class, but only about 52% would qualify based on income. The Pew Research Center found that middle-income families–in a three-person household–earned between $45,200 and $135,600 in 2016. The Brookings Institute offered a broader range, from $37,000 to $147,000 for a household of three, while others argue that the swath of Americans below the top 10% is middle class.

But you needn’t look much further than a recent CNBC story, which featured a detailed budget breakdown from a couple jointly earning $500,000 that still felt “average,” to grasp just how muddled the middle class label is. American households like that one, whose earnings could be reasonably described as “upper income,” may consider themselves middle class, or close to it. Perhaps you’d count yourself among those people, some of whom may have aspired to rise from middle income to upper income, but are now reluctant to label themselves as such.

In fact, since 1980, it’s the upper middle class whose gains have remained in step with the U.S. economy, while income growth in the middle class has lagged behind overall economic growth. So why do so many people who fit squarely in the upper middle class–if not upper class–self-identify as middle class?

The more you earn, the more you spend

Money goes further depending on where you are, which means one person’s upper middle class might be another’s middle class, and vice versa. Most people tend to measure their success and standard of living against the people directly in their line of sight. For those living in cities or suburbs with a high cost of living, their income relative to that of the folks in their orbit may seem average at best. “My take is that people who absolutely have to work in order to maintain their lifestyle, both in their own eyes and in terms of social status, feel ‘middle class,'” says financial planner Robinson Crawford.

That feeling is compounded by so-called lifestyle creep, when your cost of living expands as you earn more. The things you might have considered luxuries as a middle class American may feel necessary once you’ve ascended to the upper middle class. One couple that wealth adviser Natalie Schmook has worked with earned $450,000, which came down to $275,000 after taxes; after paying for housing, which Schmook estimates at nearly six figures, and private school costs for two children, they were likely left with no more than $135,000 in a year. “The biggest trap is lifestyle creep,” Crawford says, “and the idea that your family must continue to spend six figures a year, after taxes, to stay alive, healthy, and happy.”

Many people who misclassify themselves as middle class may simply be oblivious to how the other half lives. “One of the biggest ways to not feel like you’re struggling when you’re doing better than most of the world is to actually go out and meet the rest of the world,” Schmook says. “It’s really easy to get upset about people on welfare if you don’t bother to go out and get to know what their life has been like, and how they got to where they are. It’s easy to hate Obamacare if you’ve never had a child with a medical need.”

Even the well off don’t feel financially secure

The crux of the issue might be that Americans of all stripes were sold the idea of the American Dream–that they could hold down a good job, buy a home, and comfortably raise children. But between the rising cost of living and a changing job market, that feels increasingly out of reach for many Americans. “As housing costs have increased, you feel poorer because you can’t go out and take that next step,” Schmook says.