I dislike all the catchphrases and fad words that catch on in here and on other big forums like Slashdot. There you have to deal with "in Soviet Russia" and GNAA, here you have to deal with rock salt, pie, and other ultra-nested reply threads. People with no real input or valuable insight still want attention, so they latch onto a hackneyed catchphrase and propogate it at every opportunity, unless someone who is just as unoriginal as them got there first. Then they just quote it and repeat. A close cousin is the "REPOST" guy, who compensates for his worthlessness by scouting the forum for reposts and making sure the whole forum knows what they are. This leads to another fad of forum unoriginality, the nested repost callout. In this the first poster gives a capital 'R', the next poster gives an 'E', and so on. Of course, this leads to yet another cliche of uncharming unoriginality, the guy who breaks the R-E-P-O-S-T line with the wrong letter (ex. R-E-P-F...), as though doing so is somehow more original and clever. Pathetic.
I also dislike fad words that come into popularity here, the most annoying of which is "sammich". There are also some that leak in from the outside world, like "veggies". So many people suck so much.