I also find it annoying when multiple staff come up to me and ask if I need any help.  I always reply "no thank you", no matter how irritating it is too me.

Most of the time I go into a shop I know what I'm looking for or going to buy.  However, when I want some help in purchasing or I want to find out further information, the staff are never around or have an innate sense to avoid you like the plague.

As for buying cars and the like I get my brother to do the talking and ground work.  I happy for him to do it.  He builds hot rods, so he knows what the low down is about cars and if the salesperson is trying to pull a fast one.

Kind regards
Sarah B