Don't try to be smart by creating a brain wallet!
I've made such mistake some years ago when I was really new to crypto. I wanted to send someone my wallet address and I mistakenly sent him my private keys and I was lucky I noticed it before the recipient got the message. I quickly had to transfer my funds to a different wallet and forfeited that very wallet.
It is advisable to always have a clear head when performing sensitive transactions to avoid making costly mistakes.