People say bounds are easy to make. What makes them so easy to make?

They usually use the least amount of triggers.

Not necessarily... I'm fairly certain there are lots of that have less triggers, especially if you compare it to a quality bound. For the most parts, bounds have a simple concept, and once you understand how that works they are really easy to make(designing the levels is as hard as you wanna make it, though). IMO defenses are the easiest to make.

Yeah, Defenses<Bounds<Arena<RPG

Bounds are just simple because you really don't need to know any good triggering to make them, most just use waits.

WAITS!? OMG! WHAT ABOUT DEATHCOUNTS!?
If you wanted to, you could use deathcounts instead of waits. There really is no point though, it would be a better and easier idea to just use waits. Defenses are easier, because they essentially use only 2 kinds of triggers, creating units, and ordering units.

Well, using death counts allows you to end the bound as soon as it is beaten, something which most bounds are missing.

you forgot so much in that lmfao.
it goes like this...
madness/mass<defense<bounds<taticalwarefare<arena<RPG<OTHER MUWHAHAHA

So, two other categories is so much?