Be careful with the Steam Sale, Saints Row the Third on the first day was %75 off going for $12.49. I missed out on on the first day sale, so the very next day it was like %40 off so I impulsivley bought it.

Two days later it's back at %75 off, I wasted $23

Edit: Also Borderlands is %75 off, they had the GOTY edition for the same price, oh wait $2 more but you get all the DLC with the GOTY. You gotta watch the steam sale, if you see a amazing deal grab it. %75 off Borderlands is great, but $7.49 for the GOTY vs $4.99 for the regular, GOTY is the better value.

This probably belongs in the http://www.gamesas.com/topic/1396068-game-sales-and-deals-steam-gog-gamersgate-impulse-desura-etc/.

Did you buy it at 40% off on a non-daily sale? If so, thats an important lesson. As a rule, never buy a game unless its a daily sale or special until the last day. Even if you miss it as a daily sale, wait because it might come back as you saw with SR3. It does svck though, I made that mistake in my very first Steam sale and wasted about $30 when the games I bought all went even cheaper.

Why would you impulsively buy it?

Most other people don't need to be careful, because they're actually buying the games while they're daily or flash deals, not after.