Kano... I read this and I wonder if you found the little bumps hard because you hadn't warmed up, and by the time you reached the big hills, not only were you "psyched" and ready for it, but your thighs were well and truly warmed up and ready for them.
I have heard (in fact it was a thread here in TE) that you should warm up one minute for every year of your age... I am 40, and I before I read that here, I was finding it took me 30-40 minutes to feel warmed up before a hilly training ride, or before a race.