@Plykiya not a big deal but I would like to see it bumped up slightly, maybe 15. For me its more of what
@bigtiddyoneesan mentioned, forgetting the name of a manga and using the history to retrieve it. Doesn't happen all the time but often enough to be a little frustrating, with my stupidity not the site. Usually on oneshot binge days where I read a bunch with no intention of making a note about them sometimes I later think yeah, I want to note a oneshot that was particularly good but it's gone since it is easy to go through some oneshots. Somewhat similar are low motivation days where I just end up looking at a bunch of new mangas and get a bunch of nope, nope,... and then after awhile I change my mind on one that went by and it's off my history. Not a big deal just a nicety.
I don't care about turning it off or clearing it myself. In reference to the history vs follows list I can see a slight difference. The follows list someone would have to choose to add it to their mdlist, while the history each one gets added following or not. So someone who doesn't add hentai to their list could have it show for however long it takes to force it out of the top 3 manga in their history. A very minor problem and not one I am worried about for myself, just give me 15.