Why do people even click if they don’t want to finish the thing?

Hi, like the title says, why do people even click if they don't have the mind to finish the thing?

Yesterday I got 12 clicks and 3 leads from that and today 10 clicks and 2 leads (Pic – cpa.png attached).
Note that the CPA offer was just an email submit so FREE thing, no money is involved and people still don't finish the damn thing but will click. I just don't understand the reason behind it?

I mean if they don't have the intention to get the thing and they don't like, why would…

Why do people even click if they don't want to finish the thing?