There is a fundamental difference between philosophy and rhetoric. In order to practise philosophy effectively, we must be sincere with ourselves. And typically, the truth is painful to hear. If you're using zen stoic philosophy, for instance, what you're examining is your intentions. The emotions are the compass that point you in the direction of realizing whether there's a signal going off or not.
“The philosopher’s school is a doctor’s clinic: you should not go there expecting pleasure but rather pain.” – Epictetus
“Philosophy does not propose to secure for a man any external thing. If it did (or if it were not, as I say), philosophy would be allowing something which is not within its province.” -Epictetus
“Let philosophy scrape off your own faults, rather than be a way to rail against the faults of others.” -Seneca
"This is therefore to say that the transformation of human consciousness through meditation is frustrated so long as we think of it as something that I by myself can bring about, by some sort of wangle, by some sort of gimmick. Because you see it leads to endless games of spiritual oneupmanship. And of guru competition. Of my guru being more effective than your guru. My yogas are faster than your yoga. I am more aware of myself than you are. I am humbler than you are. I am sorrier for my sins than you are. I love you more than you love me. There’s this interminable goings on where people fight and wonder whether they are a bit more evolved than somebody else and so on.” -Alan Watts