In the Netherlands it happens a lot that when there is a group of people, you call them with 'guys'. Even if half of the group is girls, they say guys. At the end of the sentence people often stop their sentence by saying 'man'.

Does this bother any of you if this also happens in other countries? Or not so much? It does bother me even if I know it doesn't has to do anything with my gender.. and I want to get rid of those unneeded frustrations > _ <.

It's fairly common in the USA.

I like " what up dog "

At least in the western US, this happens all the time.  I do it to other trans people of either gender in meetings, even, and they to the rest of us.

I've considered it, and I must say that by and large it appears to have evolved into a gender neutral slang and I accept that usage.  It's much more polite to say "you guys" than "you people".

Also, I cite the first song of Legally Blonde the musical as evidence:

I know that "you guys" is gender-neutral, but I still don't like hearing it.  I'm not gender-neutral.

It's more common than not to call a group "guys" in the US.

Super common in Oregon. I try to avoid it if I know some of my audience is mtf. I ends up saying "folks" a lot, which is a little odd.

Happens in Australia too. Not uncommon for a group of women to be called "you guys". I know that some cis women don't like it much either,

I belong to an all women's group where we gather at dive bars in the LA area every so often.   We are collectively referred to as "you guys" more often than "you girls".

"You guys want another pitcher?"
"You guys want to try the bar next door?"
"You guys OK to drive?"
"You guys think that bartender is hot?"

No big deal.  I'm the only trans chick and I don't take offense, nor do any of the other feminists or lesbians.  We're just there to let off steam.

Around my area, people use the phrase guys and man quite often, I even have a friend that refers to his girlfriend as man, I dont mind the term guys but I dont like it when someone refers to me as man no matter the situation.

I've seen a fair bit of American basketball, and I've noted that even in the women's game they play "man-to-man" defence.  You'll also hear a female coach saying about an opposing player, "She's a great player.  We had to keep a man right with her the whole game."  A bit odd, but nobody seems to mind.