Mechanical pencil: adding lead
The issue
Mechanical pencils require users to refill the pencil lead. Ideally, users can simply open up the pencil at the eraser-end and drop the lead inside. The approach that the pencil in Figure 1 takes is to use the eraser itself as a "stopper" for the lead — the user must pull the eraser out to put the lead in. The issue arises when the eraser becomes too short to be easily pulled out. When this happens, the user is unable to refill the lead from behind and must instead insert the lead from the pencil tip, which is annoying for various reasons: it requires dexterity to fit the lead into the tip opening and it requires the user exert pressure to push the lead inside, lengthening the refilling process (efficiency issue). It increases the chance that the lead breaks during insertion (safety issue). It also just feels wrong, like it violates the natural directionality of lead movement through the pencil. Lead is supposed to come out of the tip, not go back in.
The solution
To me, the most sensible solution is to not have an eraser at all! In its place, the pencil should have a small, hinged stopper that the user can open and close with the thumb. Perhaps eliminating the eraser is too dramatic a change for most brands, but it is a reasonable fix for the particular Kuru Toga brand of pencil I have in Figure 1. Kuru Toga sells relatively high-end mechanical pencils, so buyers of this brand likely expect to be using their products for a long time. Such users will replace the pencil lead many more times than they will use the eraser. This is compounded by the fact that the eraser was tiny from the get-go, with a short lifespan and little erasing power anyways. I usually carry around large a large external eraser because of this.
The unstable water bottle
The issue
I have a short, metal water bottle with a screw lid that is attached water bottle by a flexible piece of plastic. My issue with the water bottle it cannot stand on its own when it is empty and when the lid is unscrewed: the lid extends too far out and unbalances the bottle. See Figure 3.
This is probably not a common complaint. If the bottle is open and empty, the user is likely to be refilling it at a water fountain, meaning the user is likely to be holding the bottle instead of letting it rest on the table. The exception is when the user decides to refill the water bottle by pouring from a different container. I keep a large, plastic jug of water in my room for refill purposes. Why? The water from the dispenser is too cold for my tastes, and I cannot let the water sit in my water bottle because the bottle is too good of an insulator. Hence the "third-party" storage in the jug. When I refill the bottle, I want to use both of my hands to hold the jug, meaning the bottle should be able to stably rest on the table without being held. Since it does not, I usually resort to an awkward maneuver where I stabilize the bottle with one hand and use my other hand and my body to position the jug's opening so that it rests on the bottle's opening. Only then do I start pouring. This is both an efficiency and a safety issue: it requires more concentration and time for me to do this, and it increases the chance that I spill the water. Also, if I'm not careful, the water bottle sometimes falls over before I start pouring.
The solution
One thought is to axe the attached-lid feature. However, I do like the affordance that the attachment piece provides: namely, a nice way to hold the bottle by slipping two fingers through the handle-like loop that the attachment piece creates when the lid is closed. See Figure 2.
In my opinion, a better solution is to restrict the attachment piece's flexibility so that it only bends back to a vertical position when the lid is unscrewed. This would keep the center of mass close to the bottle's central axis and fix the stability issue.
The mysterious toilet paper dispenser
The issue
I do not know how to replace the toilet paper rolls in this two-roll toilet paper dispenser (Figure 4). That is a learnability issue.
Part of the problem is that the dispenser needs to be fairly close to the ground since users will be sitting when they use it. This makes it inconvenient to see what is happening when doing anything to the dispenser other than pulling out toilet paper. Stooping down to take a look from below (Figure 5) reveals that there is some kind of covering structure that blocks half the underside of the dispenser. My guess is that only one roll of toilet paper is supposed to be usable at a time. The cover can slide from side to side in a limited way, but it does not seem easily removable or capable of opening up if the user would like to put in a new toilet paper roll. There are no signifiers for any method to do so.
The solution
I don't know how the system currently works, so I can't make any suggestions for the actual mechanics of toilet paper replacement. However, I do think that if the mechanism were changed so that the user interacts primarily with the top side of the dispenser, I would be much more willing and able to figure out how to do it.