One of the really crappy things is the loss of the casual element. Particularly just sitting with friends, taking turns, having an easygoing time.
I recall the COD4, WAW, MW2, BLOPS MW3 & BLOPS2 days (as well as R6 Vegas 1/2 & BF:BC2 & BF3, TitFall2 Pilots) with my brother. He'd be there completely baked on weed and I'd be enjoying a few beers. Just a free day and a fun, casual hangout; and it was so easygoing and enjoyable. You'd win a lot, lose a lot, hit middleground a lot, but it was a very organic experience. Now it's just sweat or dominate, super-predictable, you've gotta be sat up, eyelids peeled back, perfect grip, complete awareness and ready to pop.
Hell, in the COD4 through MW3 days I was strung out on high dose codeine while playing (had leukaemia and was prescribed it for costochondritis from steroid treatment); and I could still hang tight and enjoy games despite being in cloud cuckoo land.