How long a sentence do you want?
TBH, there are many, many cool one-liners about being a biker, most of which are already on T-shirts.
Personally, for me it's cost, style, freedom, ability, features, ease of maintenance, accessorising, wearing leather, meeting people, having friends, the open road, looking hard, attracting women, enjoying complete independence, having transport and being in control of my life, as well as many other things, the order of which varies depending on what situations are at the forefront of my experiences at whichever given moment you care to ask me.........
.....But that's just me