The thing I notice most is a lot of people buy cars (and replace them frequently) that are way above their "level" and represent hugely irresponsible decisions.
E.x. you should be way into 7 figures of wealth accumulation before you start leasing/buying $50-70k luxury cars.
You never know what someone's stock portfolio/401k/IRA whatever looks like but it's always an eyebrow-raiser for me to see someone drive up in an expensive car and then they later tell you they pay rent and have never bought property and the longer you talk to them the more you realize they're probably living paycheck to paycheck.. just with a relatively large paycheck that disappears nearly completely.
Especially when the trendy area to rent gets you a small studio or 1BR apartment for $2.5-3.5k/month and that's enough to pay the mortgage on a $1M property within 10 miles of said apartment.