Last night (well, a few days ago realistically- but last night was where it was discovered....) I proved a bit too effectively that I'm not kidding when I warn people that I can be a bit of an airhead at times.
In the course of the renovations that I did my house's main bathroom in preparation for putting it back up for sale again, I removed the toilet so I could put down the new floor under it. Since it was going to take several days for all of this to happen, I'd read that you should cover the drain hole in the floor so that sewer gas didn't back up into the house and, at a minimum, stink the place up. So, I'd thrown together a plug of sorts using an old rubber kitchen glove and some rags and stuffed it lightly into the hole. Perfect.
(as a note, at this point in explaining what was going on to my girlfriend last night that she started laughing uncontrollably as she'd deduced exactly what had happened....) -_-;
Did all the work that needed to be done, and got the new hardware necessary to reinstall the toilet. Got the new wax ring installed, the toilet positioned properly and bolted down, and the new flush valve and tank-to-bolt set put in and after checking everything over turned the water back on. Tank and bowl fill up properly at first so I was pretty pleased with myself. Then unfortunately I notice that there's water dripping in the back- so presumably one or more of the bolts through the bottom of the tank need tightening up. Damn, will have to pull the tank off and fix that.
But- also notice that the level in the bowl seems to be getting higher than it should. Initially didn't think anything of it, and figured that I should at least test flushing it and make sure there isn't anything else I need to fix while I have the tank off. So I do so- and the tank fills up to just below the brim and then stops filling. Still don't know whether it stopped because the bowl is designed to not allow more water in when it's that full or because I was just lucky that the silly adjustible flapper stopped it well before emptying the tank, but it stopped at just the right amount of time.
At this point, it's clear that there is SOMETHING not right here- I know enough about how toilets work that this shouldn't be happening. I'm wondering it there is perhaps a way an air bubble or something could be keeping it from draining properly and whether I should grab the plunger from the car when I suddenly stop and wonder, "Did I take the plug out of the hole before I reinstalled the bowl???" After some running around and poking through the garbage to confirm I can't find the ripped glove I'd used, I had to scoop all the water out of the bowl & tank and pull the whole thing back up to confirm that yes, I'm a completely idiot and had put the toilet back down without pulling out the plug I'd put into the drain hole.
Honestly, I was pretty fortunate- had the plug been a bit LESS effective, it would have been pushed down into the drain pipe and at some point gotten stuck, almost certainly where I couldn't have gotten to it necessitating calling a plumber to fix it. As it was, it thankfully didn't go anywhere and I could just shake my head and swear at it and pull it out once I'd pulled the toilet back off and the only real damage was to my pride and the lost hour it took to resolve all of the issues.