Well, I actually had to pick up the dictionary to check the exact meaning of "intelligent". It says: 1. endowed with understanding. 2. clever, quick. 3 (of a machine etc.) able to adapt in response to varying circumstances and requirements.
I answered your question so I think that shows that I am "endowed with understanding". Clever is ... in the eye of the beholder; quick I am though. I picked up the dictionary to properly understand your question and therefore, I adapted to the situation in my opinion. I don't know ... what does it really matter if one thinks they are intelligent or not? I think stupid people think they are intelligent: have you heard anyone say "No, I'm not intelligent ... actually I'm quite stupid."