How do you not beat yourself up after making incredibly stupid mistakes?

I posted here a few days ago after touring apartments and applying to sign a lease, wanting my budget to get checked over.

You guys pointed out my rent was too high. You were right. The more I thought about it, the more uncomfortable I got paying 45% of my take-home for rent. I said my take-home pay was $8k/mo but someone in the comments said... wait... did you forget about some taxes? And thank goodness, because I surely did - forgot about SS and Medicare. Shit!

Simultaneously, I had an out - my landlord had not signed the lease (there were some other issues, not the point), so I got out and started looking for cheaper places. I found one for $500/mo cheaper.

But I forfeited my $1000 security deposit. It's in the contract that if you apply for a lease but don't end up signing, they keep the deposit. Moving was already so expensive for me. That's 3% of my current income, vanished into thin air.

I just don't have the money to play games like this, but I know that as I venture into adulthood (at age 29 lmao) I'm going to make more mistakes like this and have to live with it.

What do you tell yourself to make yourself feel better?