Whenever I get cold called on the phone, when they start with 'are you having a good day?' or similar, I point out that I was until I got cold called and hang up before they say anything.
If it keeps happening, I'll ask them how they got my number, and as we're ex-directory they either go quiet and hang up, or tell me they use 'auto-dialler' software, in which case I ask them to add this number to a 'do-not-call' list.
I'm quite capable of finding good deals for stuff myself and have no time for sales people, especially ones that interrupt me on my own time.