Ways to make a good first impression

I'm always amazed at how oblivious some people are when it comes to common sense manners. For example, when meeting someone for the first time, visibly grimacing at the large mole on their face is probably not appropriate. Neither is pointing out someone's stutter. I thought I had mastered these basic, common sense rules of decorum, yet a recent event had proved otherwise.

Today I met a business associate for the first time and was trying so hard to be the smart, poised yet easy-going girl. At the end of our meeting, the person walked me to the elevator. The elevator arrived and I started inching towards it while smiling and nodding, and spurted out "Nice meeting you!" before hopping in. For the next few hours I cockily thought I made a relatively good first impression.

Then I realized my faux pas: I forgot to shake the person's hand.

I am literally mortified by my behavior. It's one of those things where you have recurring flashbacks of your idiocy and you want to smack your forehead and yell out "Idiot!" but you don't because that would be really weird.

I know it's not as bad as laughing and pointing at the disabled, but still. I should've known better.