Blazer aaaand...

[andrewrg]

What's the most casual shirt you would/did wear under a blazer?
is a polo shirt too casual for this?

[JT10000]

A cotton polo. A cotton turtleneck.

I've done the former quite a lot - even once to a summer wedding reception (actually a dark blue polo with a seersucker suit).

[DocDave]

Personal opinion. The model in that photo looks terrible. Now if you'll excuse me I need to yell at some kids to get off my lawn.

[andrewrg]

The model in that photo looks terrible.

Agreed, that's the "logical extreme" of that style, not at all one I'd wear.

[tankerjohn]

I once put on a t-shirt and blazer and looked in the mirror and....I'm just not that cool. I shall never try it again. Generally speaking, I don't care for polo shirts. I wear one occasionally in summer when its too hot for a long sleeve shirt, so I don't foresee doing it with a blazer. I guess the most casual shirt I've worn under a blazer in public is a linen buttonup shirt. Maybe I'll try a band-collar "grandad" shirt one of these days.

[meekrab]

Personal opinion. The model in that photo looks terrible.

I agree, but I wouldn't judge anyone on vacation or in college or whatever for dressing that way in extremely hot weather.