A little courtesy goes a long way....

[Steve Saunders]

I always try to acknowledge considerate drivers, e.g. those that wait behind you on a blind bend rather than squeeze past.
I have however had a few cars object to the wave of acknowledgement. One even slammed on the brakes in front of me and started mouthing off asking "what my f'ing problem was". When I explained that I was waving to say thanks for staying behind and waiting for a safe overtake they backed down, but sheesh - you can't win sometimes.
I don't bother waving anymore, just give a nod of the head now - less likely to be taken the wrong way.

 

[PK99]

I always try to acknowledge considerate drivers, e.g. those that wait behind you on a blind bend rather than squeeze past.
I have however had a few cars object to the wave of acknowledgement. One even slammed on the brakes in front of me and started mouthing off asking "what my f'ing problem was". When I explained that I was waving to say thanks for staying behind and waiting for a safe overtake they backed down, but sheesh - you can't win sometimes.
I don't bother waving anymore, just give a nod of the head now - less likely to be taken the wrong way.

i prefer to give a thumbs up rather than random wave.

 

[2Loose]

If a motorist has trundled along behind me for a minute or two waiting to overtake I ALWAYS raise my right hand in thanks as I hear them accelerate.

This ^^. If I notice a driver conciously wait before overtaking then I put my hand up before they pass.

 

[sheffgirl]

I lift my fingers up or nod my head at the nice drivers who wait at give ways for me instead of pulling out at the last minute
Hopefully they will notice, remember and be kind to me and other cyclists in future.

 

[chernij]

I lift my fingers up or nod my head at the nice drivers who wait at give ways for me instead of pulling out at the last minute
Hopefully they will notice, remember and be kind to me and other cyclists in future.

Same. Some drivers (going in the opposite direction) have even been kind enough to let me through first. Obviously I look at them and raise a hand. A simple gesture.

 

[Spinney]

In a similar way to the OP, I get pissed off when I'm cycling and pull over to let someone overtake and get no acknowledgement whatsoever.
But I usually get a smile, or a friendly wave and or toot of the horn. Much nicer for everyone...