I'm not good at remembering new knots, and not good at knowing the names of the few I know! I guess the overhand is the easiest that everyone learns as a child and can be modified to make variations for different applications.
The tensionless hitch sometimes know as the no-knot. It does not reduce the strength of the rope/cord/line at all and is as easy to tie as wrapping the rope around whatever you want to connect to. Knots often end up as a swinging **** contest to see who can tie the best/fanciest/most obscure/most trendy (read who is the flavour of the month bushcrafter and what know they use). Keep it easy and more importantly easy to undo when it's been used.
If you can't tie knots, tie lots
P.S. I teach technical rope rescue among other things and laugh at every course when someone looks at me dumbfounded when I tell them I only use 5 knots maximum.