All Gods and Goddesses are friendly,however that status of Friendly depends on several elements:
-Respect you have to Him,Her or Them.
-Their views of you as a human,person and a worshipper.
-Your gifts(Optional;but gives you that special plus in Their Hearts)
-Your prayers(Prayers when you just say Thank You,instead of constantly asking for something)
-Your Love for Him,Her or Them.
-Your loyalty to Him,Her or Them.
-Their favor to you(Gained by proving your worth to Him,Her or Them)
When someone says for example Hecate is friendly,it depends on how that person is with Hecate,She won't be friendly to everyone.
Gods and Goddesses have a Neutral stance to all people,until and if those people show that they either Love and worship Them,then their stance becomes warmer towards you OR if you hate Them,Most of Them won't have a changed stance,Some may hate you back.If you harm a worshipper of one Religion then that person's God,Goddess of More of Them will hate you even if you don't realize it and can and will harm you back one way or another.
So I strongly suggest you consult more about a ceartin God and/or Goddess OR Gods and/or Goddesses before making a first step towards One or More.If you'd like I'd like to offer you help.
Invoking and/or Summoning One isn't a good idea if you are not good to Him,Her or Them.