What to Expect from a Five Year Old Child...

Needless to say that as a mother I always try to do my best when it comes to my children. Well, my son Darie is old enough to look after himself (although I am still doing his laundry) but I am talking here more about education, about giving them some values to live by. Maybe I am out-of-fashion with my ideas, but I do think that you have, for example, to teach your child to be polite and to greet the neighbours and so say "Good morning" when they enter the kindy and to say "Thank you" when they receive something.
Maye I am overreacting, maybe I exagerate, but please, hear me out first and give me an advice, please!
My question is, what to really expect from a, let say, 5 (almost 6) years old kid? And I am talking here about Maya's collegues and friends from the kindy. Maybe I am the one that asks too much from them, maybe I am the one that is raising a freak...polite and well behaved, but still a freak.
For example, Maya has a "friend" at the kindy, same age, they know each other since they were aproximately 3...When we went to Eilat, Maya wanted to buy her and another girl a present. We agreed about something small (and not so expensive) so we bought both of them sea-shell decorated boxes. Maya was so thrilled and so she gave them the pressies as soon as she returned to the kindy...Now, her so called friend gave the box to another girl, just like that...Nedless to say, Maya was very upset and kept telling me that and also asking me why did her friend what she did. I, for the love of God, didn't know what to say...I mean, they are 5 yo kiddos, but still...I don't exactly know what I babbled to Maya because I didn't want her to be hurting and I knew I couldn't discuss with her like I would with a grown up...Maybe I should've confront Maya's friend, but I didn't want to make a big deal out of it. Still, I am asking myself now, what on Earth made that girl pass on the present she received from Maya...
There is also another girl, they are going to the same kindy only from the beginning of this school-year but know each other since they were babies, as we are neighbours. They played together in the park a lot when they were small...now, somehow, they wanted to continue with the friendship...but now the girk doesn't want to play or even talk (!!!) to Maya! Why? Well, last week we got some tickets for a movie from my husband's workplace, as a Hanukkah gift. I didn't ask Maya not to tell at the kindy, so she told her "friend" about it...And now the girl is not talking to Maya because, as she says, Maya didn't invite her to the movie as well... and Maya tells me that she is always at her  and making faces and refuses to talk or play with my daughter....Maya tried to explain that the tickets were a present and that the show was only for the people working with her dad. And truly, it was a kind of "closed door event" as we received popcorn, soft drinks, coffee and tea and doughnuts... Again, Maya is simply perplexed and sad, as she thought she had a friend in the respective girl...
So, what to do?
How to react?
What to expect from a five year old?
Is this kind of behaviour accepted for this age?
Am I ovverreacting?
Too many questions...and I really don't have the answers for them.
Nedless to say, my daughter is upset and it breaks my heart to see her hurting...

Please help me out and tell me what you think...
I am afraid that I am a bit rusty when it comes to  kids' social interaction and I fear I won't be able to help Maya when she will be older...
I want her to have friends, girl friends like I had when I was her age and to enjoy their friendship...
Oh, when it became life this complicated for a five years old?