What's the minor mistake you can't stop making

I'm not talking run enders like forgetting to reroll a tricky boss, or playing a four card hand on the final hand with The Psychic. Rather things that won't kill a run but are sun optimal and complete avoidable.

Mine is that whenever I have a "Death" card in my consumables area I will without fails use it as if it is The Hanged man. Without the description in front of my face I just go "yup let's kill these rubbish cards. DEATH it is!"

It's a minor inconvenience as I'm running one rubbish card into a slightly more (or sometimes slightly less if playing flushes and I get lucky) rubbish one. However the missed opportunity to slim my deck and the fact I may have deliberately spent some time making sure I could bring up cards I want to destroy means it is rather irksome.