I feel your pain! Some time last summer I got all pieces/parts set up. Fuel syringe loaded, tank full, stooge set and locked down with the cinder block, rolled out the release line, rolled out my control lines, started the engine for a ground run to warm up, and searched for the handle. And searched for the handle again.
Shoot!
Left the plane on the stooge, ran home and got the handle back to the plane before the sun came up too high and in my eyes. Got in two quick flights. Fortunately my circle is only a five minute drive from home. But this wasn't the first time I left something home!
Since then I use a checklist to ensure I load up before flying, and pack up after flying.
The first time I did the thick-skull pack-up, I lost/left a brand new RSM Renger 1/2A handle in natural wood/Poly-U on the pavement. I love those handles, I hated the loss! The following replacement handle is Safety Orange...I won't miss that in any light!