calm and collected

discreet laid-back mild muted reasonable reticent subdued tasteful unobtrusive

chilled controlled cool moderate plain retiring shrinking steady withdrawn

bottled-up conservative corked up in charge in check inobtrusive on a leash self-controlled soft temperate unaffable undemonstrative under control under wraps unexcessive unexpansive unextreme uptight

communicative

extroverted friendly outgoing

assured bold confident