Giraffes are pretty friendly in most cases and not aggressive.
I've interacted with giraffes and even fed them out of my hand they were very nice and gentle.
However you still have to be careful with giraffes even when out in the wild as giraffes are still wild animals, but as long as you don't seem threatening to them or try to harm them or provoke the giraffe they will most often be friendly.
Giraffes are not known to attack humans deliberately, but they can become defensive if they feel threatened or when they are startled or protecting their young.
Giraffes have a calm and peaceful demeanor, and they are often observed in their natural habitat being calm and peaceful as they browse on high foliage.
Giraffes are also social creatures which live in groups called "towers" and they also form strong social bonds, which is similar to humans, with some some individual giraffes developing close friendships.
When observing of giraffes in the wild, it's important that you maintain a safe distance and avoid startling the giraffes and most particularly avoid startling the baby giraffes.