Maji ka / Maji desu ka

Is 'maji ka' used to denote both pleasant and unpleasant surprise, or is it generally used only for when things go wrong? For example if a friend gives me a cool gift, is it okay to exclaim 'maji ka!' when I open it?

I've only ever heard 'maji ka' used in the sense of "seriously?!"

As in:
A: "I bunked off work today"
B: "seriously?!"

So upon opening a gift, it might not be entirely the right phrase to choose...

Someone else here might shed some more light

Is 'maji ka' used to denote both pleasant and unpleasant surprise,

Yes, and it means "Seriously?" or "For real?"

For example if a friend gives me a cool gift, is it okay to exclaim 'maji ka!' when I open it?

Yes, if you mean "For real?" and if it's a young friend you can talk to in a very casual tone.

I said it to a colleague who I'm somewhat close with but as soon as I said it I felt that I had done the wrong thing. She gave me a present and as I opened it I exclaimed 'maji ka? kore wa totemo kirei desu! bikkurishita! arigatou goazimasuhita!' etc etc. I really hope she wasn't offended by me using such casual language, it sort of slipped out because I hear my young students say it all the time when they're surprised. She knows that my Japanese is pretty bad and I'm just a beginner, but I really hope I didn't offend her or imply disrespect towards her gift!

Well, you did sound like a male teenage student :) It was kind of like saying "Dammit! This is so pretty..." or even "Shit! This is so lovely..."

Actually, there is a Japanese TV drama being aired now, and a character, who is a stylish and serious female novel editor in her early 20s (a real-life fashion model plays the role), occasionally uses words like "maji-ka?!" or "baka nano ka?!" and this is supposed to imply that she is a little bit eccentric and straightforward for her elegant looks.

Teenagers often use boy-ish language, but as you get older females just say "maji?" But still, "maji" is basically a slang for the youth, so if you're old enough to be a teacher, you'd only use it jokingly. Of course, females also do use "maji-ka?" if it's meant to be said in a jokingly tone among friends.

Hope it helps.

Thanks Uco!