This last weekend I had a complete clusterfuck of an internet outage. Between pulling up fiber, capping the wrong person's access point, and a bunch of tom-foolery on the part of my cable company - I wound up missing night two of my 10 man, and almost missing night two of our 25 man Ulduar.
What I did have was a wireless modem that was supposed to give me 2.0 Mbps of full duplex connection (2.0 up and down) - which is at least satisfactory. I usually play on a 3.0 down and 1.5 up connection - so I figured it'd be alright.
I don't know if it was because the connection was wireless, if it was shared bandwidth, or what - but I spent the night trying to heal while bouncing between 800 and 3000 ping - and close to 15fps. I normally run 150ms with 60fps - even during the most intense Naxx AoE fests. Now though I was struggling to land any kind of efficient heal, and I was afraid I'd have to bow out to another raider. My biggest fear of course being that of missing out on my fragments...
What happened though was that my effective healing actually went up. I had to anticipate damage more than I have in the past, and really had to push to get heals in on time. Trying to gauge the time by keeping one eye on my lag and one on health bars meant I couldn't watch the raid like I usually do (for people in fires, etc) when leading - but at least I was healing strong.
Now that I've got my fast connection back, I am trying to keep that same mentality instead of slipping back into the comfort zone of reactionary healing. Obviously we're preemtive healers in Wrath anyway (same as in BC) where you're throwing heals out knowing that at any second the tank could be dropping. With all the haste we have now, it's tough to stop those casts from going off - even with a stopcasting macro.
In short, playing with a high lag made me a slightly better healer. Though I'm still letting the ret pally die...