If a particle can decay into a lighter set of particles and still obey all of the conservation principles, they will. The heavier they are, the more they're going to decay and the more "options" they have to decay. An electron isn't going to do anything because there is nothing lighter than an electron that still carries charge, etc. Something much heavier, like a free neutron, will fall apart into a proton, an electron, and an anti-electron neutrino.
These particles have options galore as to what they can fall apart into being, and so they do, and with great haste.
If a particle can decay into a lighter set of particles and still obey all of the conservation principles, they will. The heavier they are, the more they're going to decay and the more "options" they have to decay. An electron isn't going to do anything because there is nothing lighter than an electron that still carries charge, etc. Something much heavier, like a free neutron, will fall apart into a proton, an electron, and an anti-electron neutrino.
These particles have options galore as to what they can fall apart into being, and so they do, and with great haste.