I think that in, general, showers are more confident in life, provided they are average or above average in size. They don't feel the sense of inadequacy that growers feel due to to childhood teasing or the insensitive comments of adults.
In high school we had to wear speedos for the swim team. One very popular girl referred to me as having a 'pencil eraser' down there. From that point on, my nickname was Eraser. As you can imagine, that did wonders for my personal confidence and social life.
Outside of school, there were a few times that I was invited to coed skinny dips which I promptly turned down, even though there would be hot girls there. I felt it would lessen my chances with them in the future if they saw me naked. I remember one of my friends who was probably 6" flaccid, saying to me 'dude, don't you want to rock out with your cock out, there's nothing like it!". He had no reservations at all.
In college, on spring break, my friends decided to go to a nude beach The only guys that went, all lived in my dorm (and I had seen them in the showers) and they all were all 'show-ers'. The growers all stayed back at the hotel that night drowning our sorrows.
At my first job out of college, I walked into a staff meeting, sat down and a very outspoken attention-seeking young woman across from me said "Wow, I think I am more of man than you are, I've got more down there than you do". Of course, all 20 sets of eyes in the room, focused on my crotch and, I guess, the lack of a visible penis outline. A coworker later said I had a case for sexual harassment...but there was no way in hell I was going to HR relaying that story.
Another example years later, at an office outing, someone dared the guys to go streaking through one of the days on-going meetings. The only guy out of 30 to volunteer turned out to to be the new hire and as we later found out had an 8" flaccid penis. Women in the office still talk about it to this day. I can't imagine a grower having the level of confidence to do this in front of his coworkers. From that point on, almost every single woman in the company showed an interest in him.
My point is, showers don't feel the shame about their flaccid size that many growers do, even though an erection can be the great equalizer.