I looked out at the back hill one day in May and saw a small army of purple lupines and white daisies on maneuvers up there. I didn't plant them.
I did throw some leftover wildflower seeds out there about four years ago, after trying to establish a meadow in laboriously prepared soil at the edge of the yard. The meadow didn't take --- the wildflowers were overtaken by aggressive weeds. But up on the hill, in pebbly scree that had been bulldozed and left, some of the seeds I had scattered on the rocks got their forces together and bloomed and spread and thrived.
Another gentle surprise is my kiwi vine (Actinidia kolomikta). It is supposed to have striking pink and white coloration on the tips of the leaves, but all accounts say it takes years before the color shows up. I planted both male and female vines last fall (you need both for kiwi fruits, and the male is supposed to have more of the unusual coloring).
And there --- do you see it? --- on the tips of the leaves on the right are some white splashes. I thought it was bird doo, and then I thought I may have splattered something on it over the railing of the deck. But it's the promised coloring showing up, just one year after planting. Not pink, but frosty white.
These are just gentle surprises in my garden, but they please me.
It doesn't take much.