For every contemporary classic that strides confidently on to the stage, there are dozens, nay hundreds, of plays which leave only a faint impression on the memory (to say nothing of those that are memorable only for their "why on Earth did they put that in front of an audience?" awfulness).
Goodness knows Scottish theatre needs to stage more work by women writers, for how else will we find the next Liz Lochhead or Zinnie Harris? As it does so, however, we have to accept that many of the dramas by new female authors, just like those of their male counterparts, will fail to set the heather alight.
Such is true, sad to say, of this week's plays by Chloë Moss and Marcella Evaristi.
English playwright Moss's 2008 piece This Wide Night - directed for Glasgow's Tron company by ubiquitous man of the theatre David Greig - is the more interesting of the two.
The play belongs, for better and for worse, to the socially realistic "kitchen sink drama" genre which was epitomised by Shelagh Delaney's 1958 piece A Taste Of Honey (currently seeing a National Theatre revival in London), and has been a strong strand in British theatre ever since.
Set in the dingy bedsit of young ex-con Marie (Jayd Johnson), it opens at the point when her former cellmate, convicted murderer Lorraine (Elaine C Smith), is finally released from prison.
The play is undeniably moving in its depiction of the social and personal realities for female former prisoners: Marie has been dragged back into a dangerous criminal underworld; Lorraine is desperately trying to re-establish relations with the 31-year-old son who was taken from her when he was a child; and the co-dependency of the women speaks painfully of their institutionalisation.
However, the play's realism - which is reflected in designer Karen Tennent's assiduously detailed set and in the convincingly emotive performances of Johnson and Smith - has its limitations. Typically of its genre, it prefers surface meanings to ambiguity or metaphor. Consequently, it delivers more pathos than poetry.
If the Tron's play is a modest offering, the latest piece from A Play, A Pie And A Pint is simply disappointing. Written by and starring Marcella Evaristi, The Friends Of Miss Dorian Gray is a poor and far less witty imitation of Oscar Wilde's only published novel, given a modern twist.
Dorian Gray - now depicted as a 21st century, female performance artist - is 50-years-old. Her physical appearance seems unchanged in 30 years; so much so that her friend Dolores (Evaristi) suspects that Gray's latest art work (a bold statement about plastic surgery in which Gray writes upon her naked body) is less about feminist solidarity and more about narcissistic exhibitionism.
Add to this a disputatious mutual friend, Daisy (Janette Foggo), an experimental dermatologist (Tom McGovern) out of his depth, and Daisy's never seen, cocaine-addicted, lesbian daughter and you have a piece which is too overloaded for a 50-minute play; indeed, it over-runs by 10 minutes (a cardinal sin for A Play, Pie And A Pint show).
But worse than her play is Evaristi's decision to cast herself in it. Verbally stilted, visibly (and amateurishly) anticipating each line, she moves with all the natural ability of a star of The Lego Movie.
Were it not for the mediocrity of her script, I would suggest that she stick to writing.