I ride a bent, so I'm not talking to the comfort issue, i think others have some good suggestions. But, I did want to re-iterate, you don't have to wear cycling shorts!
If you want to fit in, there are a number of jogging/fitness short or rowing short options that look just like cycling shorts but have little or no padding. These shorts will also likely be more comfortable on longer rides on your thighs and knees than jeans (I would expect).
I personally love rowing shorts, which have a little bit of a pad, more for modesty than anything else, and look like bike shorts. These are some of my favorites
http://www.jlrowing.com/