OK, let's be positive for a chance:

I've lots of eateries and noodlestalls to recommend up my sleeve, but let's start with these two:
Chiang Rai, Yetrod Rd., opposite the Chinese temple:
there is a tidy looking place with comfy wooden benches which does an assortment of Thai-style dishes in the 50-60 bt range. Enormous portions (by Thai standards), good for 2 backpackers at least, and very tasty.

Further to the right, an eatery which looks more like what you're used to from travelling, corrugated iron and plastic sheet roof, with matching facilities. Premises rented from the wat. But, a neat Rice-soup for breakfst (20bt) and a choice of vegetarian and 'normal' dishes. The Cordon Blue with French Fries was good and filling (120bt), though the fries were a bit soggy, i.e. undercooked Brit style.