their tricky methods

I’ve decided to don’t attend any politic parties and, don’t debate with anyone about politic. It’s my personal decision and, all are dependent on me.
Some days ago, someone who I know him in some ways, called to invite me for a seminar about philosophy. He knew that I like this topic. I checked my schedule and said that I’d attended on that occasion because I was free at that time. He called me the next day and the day after it.
I went to the seminar, the topic was my favorite, but the speech wasn’t at a top-level. It was not bad, not good either. Briefly, I can say that it didn’t add me a lot.
And I just knew something that it’s bothering me. The speaker of the seminar is a parliament nominee and, that seminar was a part of his advertisements for the next election.
I’m upset with myself, because of relying on everyone. I cheated.