He was a right geek as a kid
In a letter to his mum, he straight up admits that he's thought his life would be spent with books, but as soon as he started to hang out with the cool kids, he realised that he wasn't making friends with that attitude. So he took up dancing and fencing, which meant that, even if no-one liked him, he could stab them up.
(Letter to Justina Salome Lessing of 20 January 1749)
He thought that The Bible was too long
Even in the post-modern world, where everything is everything and 'cross-discipline study' helps gets scholarships, Lessing the dramaturg and Lessing the theologian get treated like separate people. I actually have to keep checking that the Lessing who wrote in defence of what would now be seen as a 'liberal' Christianity is the same guy as the author of Laocoon.
Grappling with the competing inspirations of his Lutheran upbringing and Enlightenment reason, Lessing stood up for 'the inner truth' of Christianity. Roughly, this meant that all that stuff in The Bible about history was too much information, and he hoped to find somebody who could teach the Christian message 'like Jesus would have done'. He wasn't exactly asking for A Beginner's Guide, but he is unlikely to have had much sympathy with the fundamentalist's insistence on the absolute truth of Genesis.
He was a Social Justice Warrior
Spend five minutes on YouTube, and a neckbeard will appear, explaining how the Enlightenment Project is being destroyed by Social Justice Warriors. Apparently, the worship of science, penis and playing computer games is the logical end of the Age of Reason, and those people who, like, promote feminism and are against Islamophobia are Cultural Marxists plotting to destroy civilisation.
Only, Lessing was all about the egalitarian and the cosmopolitan. His play Nathan the Wise featured a wise Jewish dad who told a parable which explained the equality of the three monotheisms. In fact, Nathan even hints that the Jews are wiser than the Christians. It's a shame that this parable is still relevant today.
He was the sweet talking son of a preacher man
Oh yes he was. His dad was a Lutheran pastor.
Even after his death, he was causing a right ruckus
Following Lessing's early departure from this mortal coil, two of his mates, Moses Mendelssohn and Freddy Jacobi threw down over which one of them ought to be considered his philosophical heir. It was a controversy that lit up the German intellectual scene. To be honest, it all reads as a bit trivial to me - it seems to be about whether Lessing ended up supporting Spinoza's pantheism or retained a more orthodox position on theism. But it might have had some importance in the shift from Enlightenment to Romantic modes of thinking, so there's that.
Source: Lessing's Philosophy of Religion and the German Enlightenment (OUP, 2003)