Hi Hugs,
This is a hard question. There are always other factors when making a decision, so I would even go as far as to say that no decision would be entirely rational.
Did you really want to go? Are you thinking now that you should've went? I guess that's the only way to tell, if you're not that concerned that you didn't go then you probably didn't really want to in the first place. But if it's really playing on your mind then you should make sure you're at the next one :)
"Never regret anything, because at the time it was exactly what you wanted." I love this quote.
Kaitie.
P.S. What's an open house? I always thought that was when real estate agents allowed vendors to come and look at a house their selling? :S