The feeling of people ignoring your texts and festival greetings, and only return to you when they need help is bad. Would you consider them as your friends?
How about someone who spams you to LIKE certain photo for a Facebook competition and becomes hibernate when you ask for a return favour to LIKE yours?
They are lower-grade than hi-bye friends.
If you have met such people, don’t bother to get angry because they are just everywhere. Nevertheless, they do give you the assurance that they are not worth much of your time. Skip them and spend your time on better people.