When I started out in botany the first field guide I owned was McClintock and Fitter's Pocket Guide to Wild Flowers, which used a one-, two- or three-star system to indicate rarity. And I was obsessed with finding rarities (though not very successfully). I still get a buzz out of finding something uncommon but have come to appreciate the subtle charms of the less ostentatious wild flowers, realising that if you can't see anything interesting about a plant then you probably aren't looking closely enough.
Here's a case in point: knotgrass Polygonum aviculare. This is the rather attractive little flower, which is only a few millimetres in diameter ......
...... and this is the scruffy plant, growing in a gap between the paving stones in our garden path. I must have trodden on it scores of times as I've been walking up and down the path, but now I've looked more closely at the flowers I tend to step over it.
Its tiny seeds probably provide food for the sparrows that are always fossicking in the crevices in the garden path.
In his Weeds and Aliens (1961) Sir Edward Salisbury mentions that in sandy soils the tap root of this tough annual can penetrate to a depth of three feet and that its seeds remain viable for up to sixty years.