"A sure cure for seasickness is to sit under a tree."
The origins of the quote may actually date back to Admiral Lord Nelson (yep, the fella from the Battle of Trafalgar). I think it definitely sounds like something Spike Milligan would have said in his own inimitable style.
The meaning attached to the quote is also up for interpretation but I think the simplest meaning is that if doing something makes you sick (annoys you, you don't like it, etc), stop doing it!
If you want a situation to change then you have to do something about it.
Source: Spike Milligan