If your refering to sellers, you also have to consider they have a biz away from online and probably get a ton of pms ect... during the day to check in between their biz work... the time they may be on looking about the board may be inbetween pms or just getting in a break from the daily job.....the fish buying/wanting side of it on your end may be a crippling urge to get it now and fast whereas the seller may just be trying to get the days messes straightened and things moving ahead smoothly....patience 
or it could be him/her blowing you off as a pain in the *** saying "would he quit f#%#ing pming me already" ....heh heh heh
or it could be him/her blowing you off as a pain in the *** saying "would he quit f#%#ing pming me already" ....heh heh heh