Take one Olymopus E-M10.
Start with the "kits" lens' 14-42mm and 40-150mm.
They work and get some good pictures.
Add the 25mm f1.8, now that is a step up in sharpness and just a better picture.
Add the 45mm f1.8 and the results again move onto another level, that has become the goto lens.
There are lots of desirable lens' but costs sky rockt quickly so the wishlist remains unfulfilled and tthe 60mm macro, 12mm f1.2, 75mm f1.2 and any of the new pro range remain in the shops.
But all is not lost.
A pair of extension tubes (10mm &16mm from "Meke" on Amazon, something like 30) produces good macro results, pleased with that, another set added good make for some interesting results.
Today a step further.
I read a article (I don't have the link, it was on an RSS feed and it took a few days for the content to percolate through) about connecting an old Canon lens to a body and getting some impressive results. Again a trip to Amazon to find that a cheap and cheerful OM to M4/3 converter is 6.99.
3 days later...my uncle's old Soligor 500mm mirror lens is strapped to the front of the camera, it is rather large and most certainly the part that needs a tripod.
Here is the scene taken with the 25mm lens.
Photos are duly taken, focussing is much harder and there is a noticeable wind in the garden today which does little to assist. The Oly's 2x magnification helps little with focus because the wind effect is magnified close up.
Here is the same picture with the 500mm mirror lens.
Ok so there must be a loss of focal length because the converter is essentially the same bit of kit as a macro tube (must try that!) but with a 500mm lens attached to a 2x crop factor camera I have something like 1000mm of lens and I am thinking moon photos.
Returning indoors to the bag of camera bits to find an end cap to discover an OM2x converter, so 2000mm is looking good.
Here is the same picture taken with the 2x converter and the 500mm lens, I gave up attempting to focus a this point.
Lastly, just to test I attached my dad's 50mm OM f1.8 zuiko lens and took the same shot again.