Mine's place_meeting(x,y,object). So versatile and useful; everyone who's read my "why not to use solid" article on my blog will also know why I like that function so much.

What's yours?

Mine is one I added "create_object_ext(x,y,obj,speed,direction)" Its nice not to have to write that extra little bit to get the same results.

That's pretty neat. I didn't even think of custom made functions.

My favorite that I wrote to make my own life easier were probably my HitWall function (which checked dynamically for wall collisions taking into account one-way platforms WITHOUT the need of a second wall object) and TurnAngle (which turned an angle to a destination angle while being able to transverse the 359-0 boundary).

I made my own grid drawing function. I actually made it into a D&D action as well. It's annoying to have to type up those two for statements to get the simple result of a grid.

Hip hip for making life easier!

Just remembered another favorite that I made 'draw_rectangle_sprite_mouse(sprite,image,color,alpha)'
It was for rts games, it draws a rectangle for selecting units but makes the rectangle's lines a certain sprite.

My most favorite function would be any of the string functions but to be more specific string_copy and string_replace_all. Very usefull when always working with strings.

I don't have many custom scripts but I guess my favorite would be text_to_bytes. It just converts every letter in a string into bytes to make secret yet not-so-secret messages.

Mine too is place_meeting(x,y,obj). It is by far the one I use most often.