well, or see patterns where they exist, but where we lack the will or knowledge to explain them properly. generally this does not really matter, its an easy way to explain anything to a satisfying level, usually.
for example:I knew people who had chronically slow wifi in their house. Their standard explanation was that the neigbors would connect to the wifi, download over it, and slow things down. stopping and restarting the router seemed to make things go faster, so if things were lagging they would do that.
in reality there were no neighbors on their connection (or they were clever enough to spoof their mac addresses and host names to match those of devices used by the house's owners), and I assume that the router restart just forced things to stop for a bit, if a dl was running it would be resumed later.
Basically, they just had a slow internet connexion and often they would overwhelm the bandwidth. haxx0r neighbors sounds cooler though.