Why are electrophilic addition reactions the characteristic reactions of alkenes?
Here's an electrostatic potential map for ethylene,
Where red indicates high electron density.
In ionic reactions, what has the most electron density?
Hence, addition reactions of myriad of materials (an electrophilic addition occurs first in most mechanisms) about the planar double bond with different regioselectivity and stereospecificity are the most common reactions.
Here's a non-exhaustive list of a few ways we can leverage