I get laggy SMS from time to time. Force quitting it, or any other lagging app, fixes it temporarily.
What I think is funny is all the peeps who installed 2.0.1 and immediately declared that it fixed this lag or that lag. Of course it seemed to fix a lot of things, because installing firmware reboots the phone, and rebooting flushes the RAM. Sure enough, as more time passes after the update, people are starting to complain of the same problems they had before the update, as the effects of the reboot wear off.
Everyone is friendlier after a nice nap. Doesn't mean they're a totally different person.