For me, it was this entire past year.
On Jan 7th, 2012 I bought a Percheron mare so that I could trail ride with my wife. She is a magnificent creature and I was just just getting to know her, I think I rode her twice; on March 29th, she threw an unexpected colt. I have since been learning all kinds of new things that I never anticipated learning. Also, her throwing the colt seems to have greatly enhanced our relationship.
Before she had Ricky Bobby, we were really just getting to know each other. She was a little unsure with me and I was certainly unsure with her (being my very first horse ever and all). Before Ricky, I was apprehensive about doing things like picking her feet up or working around her hind side. For example, I would clip her blanket leg straps around each leg instead of crossing them between the legs. I was just unsure about things... After Ricky was born and increasingly so since, I have NO issues doing ANYTHING with her. I've been all over her doing everything I need to do, and she in turn is used to me and is like a huge baby now. I obviously earned her trust or something... I remember when I first saw Ricky standing next to her in the stall. She really did look scared, almost like she was uncertain about what I would do or if I would take him or something.
Both times I rode her before she had Ricky, she was stubborn and didn't want to move, etc. I didn't ride her again for a few months, but when I did mount back up again, she was still stubborn and difficult in general. I had our trainer assess her and we all thought perhaps she was greener than we thought.
Then.......... One day after we weaned her, I readjusted my stirrups and found my seat! It's been game on since.... Turns out she's not green at all, she just knew that I was green. Since I've found my seat, I don't get discouraged if she side steps or tries to refuse. I ride through anything she gives me and persist. Since I took the right mindset with her, she has completely turned around and is an absolute pleasure to ride.
Anyway, long story short, this entire year with a new horse and a new foal and new to the whole horse thing myself has been a major accomplishment for me...