Install an SP3 or TR4 socketed CPU in a dusty, dirty room without ESD precautions and crank the torque on the top plate and heat sink like truck lug nuts until creaking and cracking noises of the PCB delaminating are noticeable. Also be sure to sneeze on the socket's chip contacts and clean it violently with an oily and dusty microfiber cloth to bend every pin.

c. 2004 and random crap on eBay: DL380 G3 standard NICs plus Cisco switches with auto speed negotiation on both sides have built-in chaos monkey duplex flapping.

Google's/Nest mesh Wi-Fi gear really, really enjoys being close together so much that it offers slower speeds than simply 1 device. Not even half speed, like dial-up before 56K on random devices randomly.