Many people criticize the way some problems have been solved, complaining about the buttons, love, songs, deux-ex-macchina and various other solutions. But no one has ever said how it should look like.
So, what do you think, what is the best way to resolve the problem in DW episode? What kind of solution do you prefer?
Which episodes had the best and which had the worst endings?

One of the best and most clever has to be the ending of Day of the Moon. The "you should kill us all on sight" revelation was on par with the "I AM SHERLocked" revelation in Sherlock, in my opinion.
The end of the The Girl Who Waited was also good, not because it was particularly clever, but because it sort of portrayed the Doctor in a negative light as he lied and manipulated his companions in order to save Amy.