Debt is a killer. I used to have a lot of credit card and personal debt, and was paying over $1,500/mo in interest on less than $100k USD/year. If you get stuck in that trap it's damn near impossible to get out of if you overextend yourself.
A lot of folks grossly underestimate what they spend eating out and drinking. Probably less of a problem now than a few years ago, but coinciding with my credit card debt phase I would have told you I spent "$100, maybe $150" a month when it was closer to $400-500.
If you're not set up for retirement (see below) there's little to no reason to be leasing a brand new BMW. I was absolutely guilty of this and it's tens of thousands of dollars I essentially set on fire for three years. You don't even have to sacrifice the nice car, my 2016 5 series was less than $25k out the door and I got it right after someone turned it in off-lease. My payment is less than theirs was and it'll be paid off before the warranty runs out. I'll then have an "asset" (not really) worth $5-10k, and can get another $25k off-lease car which will cost me less and get paid off quicker, if not in cash.
If you max out your 401(k) you are saving about $20k/yr while only reducing your taxable income by ~$15k/yr depending on your marginal tax rate. A Roth adds another $6k to that if you're under the cap (something like $140k for 2020) and you can withdraw the contributions from that account at any time without penalty. Not helpful for someone making $40k/yr but if you're making $100k it's hard to make a good argument not to max out your retirement unless you live in one of the outlier cities as far as rent and expenses.
There are absolutely the /r/personalfinance types who act like if you go to a restaurant more than once every six months you're going to end up destitute and starving while homeless. And the FIRE community is a borderline cult. But nobody working in our industry, even in super high-COL areas, really has to worry about retirement, even if they've made dumb mistakes like I did that ended up costing hundreds of thousands in the long run.