What is proof of humanity?
Machines only do what is logical. The best proof of humanity lies in unpredictability and randomness. Much of what humans do is illogical.
If you want to make an AI seem more human-like, make it do and say some things that are random or illogical.
Willingness to sacrifice oneself for the benefit of another. It doesn't make any sense, but it happens when there is love.
2. Approval seeking
Doing things to get approval of others. So you just bought the bar a round of drinks. That makes no sense logically. But you may have gained something in intangible relationships and status.
Addiction is purely in the realm of sentience. Your body says it needs something and you should do almost anything to get it, but you really don't need it.
4. Excitement seeking
Machines don't get bored. Your computer can calculate pi for the next thousand years and never get "bored." After humans do something for long enough, they have an urge to just do something different.
5. Pleasure seeking
Seeking pleasure is illogical. You do something for a certain gain, but the gain is extremely short-lived. Doing it doesn't really give you any long-term benefit, so it's illogical. Machines won't see a point in seeking pleasure. But humans do. Because someday when an 88-year-old human is sitting in a hospital bed with her body failing, she will think back at those moments of pleasure from the past, and she will feel good again.
Suicide doesn't make any sense, but it happens among humans. A machine would never contemplate suicide.
7. Random actions
Machines do things for a reason. Either they were programmed to do it, or there is a certain gain from doing it. But humans often do things without thinking it over and for no reason.
Faith makes no sense. People believe in all sorts of things, even when there is no proof that they even exist. A computer doesn't believe in God, I can guarantee that.
9. Following your gut
Similar to faith, you get this feeling with no concrete evidence to back it up. That's not the part that proves humanity. No, the part that proves humanity is if you actually take action because of that feeling.
10. Sense of purpose
A machine may have a purpose, but it is known all along. A human may have a purpose, but it is not known until much later.