WWI created a huge mess in its wake, particularly in the Middle East, where much of the border-redrawing occurred. The Ottoman Empire, previously a fairly major force (though it had been losing territory), was entirely carved up - it retained only Anatolia, which soon became Turkey, and under unfavorable terms. The short version of the story, which can and has filled books (see, for instance, Justin McCarthy's The Ottoman Peoples and the End of Empire), was that many, many people died, new governments and governing structures replaced the old (especially through the emergence of national governments with homogenizing missions in what had previously been a diverse, multi-ethnic empire), and the economy was in many places devastated by the wartime destruction or misuse of farmland.

This answer applies to the Middle East after the war - during the war, border changes were slow. World War II saw massive territorial gains and losses, but WWI was primarily defined by trench warfare on the Western Front and minor internal revolt in the Ottoman context. Thus, the most important military progress at the important battle sites was measured in yards and handfuls of miles, often at the cost of tens or hundreds of thousands of lives. The war didn't conclude because of major territorial shifts, but because of economic attrition - Germany was broke and couldn't continue. And I'm fairly sure that not many people who weren't actively involved in the fighting wanted to be anywhere near the front. So, in sum, the important territorial shifts associated with WWI occurred after the war. (There were shifts before the war - the Ottoman loss of the Balkans led to similar turmoil in the formation of national states and crisis in the Balkans certainly factored into the beginning of the war.)

I can't answer your question, but I can provide some contemporary perspective. The northern border of India is still highly contested, to the point that Google Maps doesn't even have a definitive border for many miles.

I'm not sure if this violates the rules because it's definitely in the realm of current politics, but looking into how it affects people today might give you some perspective on how it affected people in times past.

Additionally, "hard" borders are a relatively recent convention. Borders were defined by areas that nations, governments, lords, etc. could control, and most had significant buffer zones between them defined by geographical features that couldn't really be "held" (dense forest, impassable terrain, what have you).

During WWI this probably wasn't the case (not something I know really anything about), but being that contested borders were not something alien to the peoples of Europe, I don't imagine it really affected their lives as a standalone convention in a meaningful way. Obviously war affects peoples lives profoundly.