Is it possible to be more genetically related to an aunt than a parent?

I was reading in my course books last night that you share a probability of genes of ½ with those closest to you; parents, siblings, offspring and that it decreases to ¼ in relations such as grandparents, then 1/8 to cousins.

Now I don’t know much about genetics so please humour me here. But, is this just a probability? Meaning that it’s possible that one could share more genetic code with an aunt than a parent?

Furthermore, can someone tell me why exactly, genetically speaking that the offspring of two parents, don’t all ‘turn out’ the same…they don’t have the same genetic code?.. I thought that the chromosomes of two parents come together to create a new strand…why isn’t it the same strands for each child?

Thank you x