Unfortunately, for those that actually utter things like this (the younger me for example) a list of "what not to say" is not going to explain "why not", which is the most important part. That usually comes with experience.

I just added reasoning next to each quote on why people regret saying them.

Out of curiosity, how old are you?

I was founded in 1981.

Thank you. I have met people who say things about their "younger selves" when they were 20. Wanted to know if there was enough time difference between you now and you then to take your comment to heart.

Things First-Time Founders Regret not saying more often:

"No."