There's something inorganic, and therefor disingenuous. about quotes from historical figures or celebrities. There is an unrelatable diconnect. It just doesn't feel "real." It functions more like a piece of propaganda, only carrying significance for those who have already fully submitted to its ethos.
To the rest of us, it is registered as a meaningless annoyance and promptly blocked out before its message can be delivered. People who actually use their brains respond much more positively to organic self-expression, even if it is less powerful or elegantly worded, than a Gandhi repost or a Neil Degrasse Tyson meme. Even when it is flawed, natural expression is more engaging and feels truer. More constructive conversations begin this way. Quotes from historical figures or current celebrities tend to incite ignorant screaming matches of a caliber only slightly higher than that of a religious debate.
You may find yourself writing a page of material before you choose just the right words, but I believe it is worth the effort. I mean, just look how genuine the previous sentence feels. There is a famous quote that says the same exact thing. Yet, if I were to have used that quote, I would have come of a bit preachy and pretentious. Instead I use my voice to speak my message.
Speak what you honestly believe, from an unguarded, slightly afraid place inside of yourself, or no one is going to give a shit.