First impressions are everything. I'm not saying to pretend you're someone else on the first date (or first speed dating event), but you do want to show your best side. True story, I ended one date with a kiss on the lips from my date who just smoked a cigarette (my fault for letting it happen---and yes it was more gross than it sounds) AND he left the toilet seat up. Call me old-fashioned, but if you are a guy, and you come into MY apartment, I don't care how messy it is you do not leave the toilet seat up in a girls' apartment.