It's not the norm but it does happen quite a bit, especially in authoritarian countries at land borders where the officials are always looking for a way to justify their jobs. It happened to me last year and that was in China, although in that case leaving not entering.

PS: for info, that was in Xinjiang at possibly the highest security border in the world. I showed the official a bunch of my mundane tourist photos, which was enough to have me on my way. Not a pleasant experience though.