Trust yourself. And don't short naked calls.

Following a certain youtuber's patreon trade for options in his 10-100k challenge. Went in despite my own analysis indicating otherwise. Cost me over 10 grand over the course of about 9 months. Lesson learnt to trust thyself!

Also shorting call options without proper hedging. Basically picking pennies in front of a freight train - not worth it.
Cost me a few grand over the course of a year. If conviction is not there, then usually better to just close a long position or short the counter. Selling naked generally not a good idea.