How bizarre this one is. The Sun is all about the love of life, joy, banish darkness, celebrate living and a very charismatic individual whereas The Devil is about control, temptation, obsession, over-indulgence, etc. So one can assume, rightly or wrongly, that the person may be under the control of a very charismatic individual for example or even that their sunny outlook on life is controlling their decisions to their detriment i.e. they are not seeing the fuller picture. It is always best to see both sides to any situation even if you are a 'glass half full' person.

What spread were you using? The position of the cards will also have a great bearing on their meanings

Interesting take on it.. thanks