I haven't filed any Canadian tax forms....ever.

[Whose Wandering]

Ok, time to grow up, I know.

So I've been living in Thailand for 1.5 years and I haven't touched any tax forms.

Will there be any problem with me getting into and out of my sweet homeland?

And should I file something? Could I actually be receiving a tax refund of some sort somehow?

[Jet Gorgon]

^ Canada has dual tax treaties with Thailand (ie, if you pay taxes in Thailand, you don't pay any in Canada). If you don't work and have no Canadian earnings, you are fine. If you have Cdn earnings, like interest, capital gains, then those should automatically be deducted by the bank/issuer if they know you are overseas. But, you have to check your CPP if you want pension should you go back to the frozen wasteland.
Tax refund.. if they owe you, the check's probably laying dormant in your old mailbox. Cdn Revenue tried to get me for taxes owed on my last return (1984). It relented and said I owed less than C$2. Only took em eight months to figure that out.