My bigger ‘stuck or lag’ problem is when a weak network signal puts me into the seemingly-endless wait state with the ‘spinning disk of death’ (the network wait icon) spinning, and spinning, and spinning, and spinning, ad infinitum. It strikes dozens of time a day at my favorite park for playing, usually denying me the chance to use a particular berry or to try to catch a particular pokemon (a few months ago Niantic added a ‘fix’ that the pokemon would eventually disappear from the viewer after the game timed out, an error msg would show across the top, and then a few seconds later another pokemon just like it would spawn close to the same location).
A related-but-somewhat-less-common system failure happens when fighting gyms or raiding: Last night my net connection became too weak right when my first Giratina raid countdown ended, and the GO never showed up. Even worse, it hit again an hour later after a group I raided with beat a Giratina boss, while my fourth throw was trying to capture the defeated boss. (That latter net flakeage barfed my trainer back outside of the gym where the raid had happened after about 10 seconds of that net-wait icon, an error message flashed across the top, and it acted as if I had never even tried the raid, except I got to keep the raid-reward potions, revives, and stardust). So I was locked out of the whole raid in the first case, and was robbed of 9 more post-raid capture tries in the second case.
(whine whine whine…)