Yes, some people in America think that all their friends need to come see them get tattooed. Some people live in their own special bubble.

From your earlier post I assume you're in Russia. I'm across the pond, so if tipping isn't a cultural thing for you, you'd have to go in and speak with an artist or someone else that knows more about that in your area. Here, we still pay a pretty high price and tips aren't required, but if you feel that the artist did a particularly good job, something extra can go a long way to fostering a positive relationship as a client. I personally don't like tipping culture, but it is what it is and I'd rather dislike it on my own time and not be an asshole to the person receiving the tip.

Basically, just like you said, be a decent human being. You're going to potentially spend a lot of time with this person. It's going to be much more pleasant if both of you are amicable. If you need a break, take a break. Your artist is probably going to do the same, because their hand is going to get tired. Try not to disrupt them too much, if possible. You don't want to have to take a 5 minute break every 10 minutes.

Some additional tips

Bring in a basic sketch or even a printed out picture of what you want. Allow the artist to recreate or stylize the picture and look over it with you. Some people charge for the pictures and some don't. It's typically considered good etiquette, at least over here, to offer them some sort of compensation for their time and work, even if you don't end up getting body work done by them.

Artists typically have to rent space in the shop owner's building and pay a % of what they make on the tattoo, as well as buy their own supplies. This is why we end up tipping, because that money goes straight to the artist and the shop owner doesn't get a cut. If you get work done by the owner himself, just ask if he accepts tips or not. Again, not applicable if that's not in your culture.

If you make an appointment, stick to it. Cancelling really hurts the artist because they typically rent the space for the day to do work and have to pay the owner even if the client doesn't show.