The major issue or problem that American soldiers faced in Britain during WWII was that (as the old British joke went), they were "overpaid, oversexed and over here." (This saying sometimes included the word "overfed" as well.) The idea is that Britain had to deal with hundreds of thousands of young men who were in many cases away from home for the first time and had certain advantages over the local men in terms of competition for women.
The American soldiers generally had better material standards of living than the regular British people. America was a much richer country and could afford to give its soldiers good pay, good food, and other things like cigarettes that were seen as very valuable. This caused problems of a sort for American servicemen. They had to be careful not to cause problems with local people while, at the same time, they of course wanted to socialize, particularly with women. They therefore had to try to walk a fine line, using the advantages that they had while at the same time not being overbearing and causing major problems with the local British populace.